diff --git a/include/exiv2/error.hpp b/include/exiv2/error.hpp
index 31a9e7f5..7eb7923f 100644
--- a/include/exiv2/error.hpp
+++ b/include/exiv2/error.hpp
@@ -14,8 +14,9 @@
 // *****************************************************************************
 #include "exiv2lib_export.h"
 
-// included header files
-#include "types.hpp"
+#include <bits/exception.h>   // for exception
+#include <sstream>            // for operator<<, ostream, ostringstream, bas...
+#include <string>             // for basic_string, string
 
 // *****************************************************************************
 // namespace extensions
diff --git a/src/basicio.cpp b/src/basicio.cpp
index ddbc81f3..b5280ed6 100644
--- a/src/basicio.cpp
+++ b/src/basicio.cpp
@@ -14,9 +14,7 @@
 // + standard includes
 #include <fcntl.h>      // _O_BINARY in FileIo::FileIo
 #include <sys/stat.h>   // for stat, chmod
-#include <sys/types.h>  // for stat, chmod
 
-#include <cassert>
 #include <cstdio>   // for remove, rename
 #include <cstdlib>  // for alloc, realloc, free
 #include <cstring>  // std::memcpy
@@ -24,8 +22,6 @@
 #include <filesystem>
 #include <fstream>  // write the temporary file
 #include <iostream>
-#include <memory>
-#include <string>
 
 #ifdef EXV_HAVE_SYS_MMAN_H
 # include <sys/mman.h>                  // for mmap and munmap
diff --git a/src/bmpimage.cpp b/src/bmpimage.cpp
index 14f73799..78416cfd 100644
--- a/src/bmpimage.cpp
+++ b/src/bmpimage.cpp
@@ -4,8 +4,6 @@
   Author(s): Marco Piovanelli, Ovolab (marco)
   History:   05-Mar-2007, marco: created
  */
-// included header files
-#include "config.h"
 
 #include "basicio.hpp"
 #include "bmpimage.hpp"
@@ -15,7 +13,6 @@
 
 // + standard includes
 #include <cstring>
-#include <iostream>
 #include <string>
 
 // *****************************************************************************
diff --git a/src/canonmn_int.cpp b/src/canonmn_int.cpp
index 260dd688..3cb04e09 100644
--- a/src/canonmn_int.cpp
+++ b/src/canonmn_int.cpp
@@ -20,10 +20,6 @@
 #include <string>
 #include <sstream>
 #include <iomanip>
-#include <ios>
-#include <algorithm>
-#include <cassert>
-#include <cstring>
 #include <cmath>
 
 // *****************************************************************************
diff --git a/src/canonmn_int.hpp b/src/canonmn_int.hpp
index ea6ba528..ca6d8ced 100644
--- a/src/canonmn_int.hpp
+++ b/src/canonmn_int.hpp
@@ -17,7 +17,6 @@
 // *****************************************************************************
 // included header files
 #include "tags.hpp"
-#include "types.hpp"
 
 // *****************************************************************************
 // namespace extensions
diff --git a/src/casiomn_int.cpp b/src/casiomn_int.cpp
index 520bf6e1..aced7ab8 100644
--- a/src/casiomn_int.cpp
+++ b/src/casiomn_int.cpp
@@ -12,10 +12,8 @@
 #include "i18n.h"                // NLS support.
 
 // + standard includes
-#include <string>
 #include <sstream>
 #include <iomanip>
-#include <cassert>
 #include <cstring>
 #include <vector>
 
diff --git a/src/convert.cpp b/src/convert.cpp
index 80d07bab..0c5224ab 100644
--- a/src/convert.cpp
+++ b/src/convert.cpp
@@ -19,14 +19,8 @@
 #include "unused.h"
 
 // + standard includes
-#include <stdio.h>  // for snprintf (C99)
 #include <algorithm>
-#include <cstring>
 #include <iomanip>
-#include <ios>
-#include <iostream>
-#include <sstream>
-#include <utility>
 
 #if defined WIN32 && !defined __CYGWIN__
 # include <windows.h>
diff --git a/src/cr2image.cpp b/src/cr2image.cpp
index 00b28113..546a197d 100644
--- a/src/cr2image.cpp
+++ b/src/cr2image.cpp
@@ -1,23 +1,15 @@
 // SPDX-License-Identifier: GPL-2.0-or-later
 
 // included header files
-#include "config.h"
-
 #include "cr2image.hpp"
-#include "tiffimage.hpp"
+
+#include "config.h"
 #include "cr2header_int.hpp"
-#include "tiffcomposite_int.hpp"
-#include "tiffimage_int.hpp"
-#include "image.hpp"
 #include "error.hpp"
 #include "futils.hpp"
-#include "i18n.h"                // NLS support.
-
-// + standard includes
-#include <iostream>
-#include <iomanip>
-#include <cassert>
-#include <cstring>
+#include "image.hpp"
+#include "tiffcomposite_int.hpp"
+#include "tiffimage_int.hpp"
 
 // *****************************************************************************
 // class member definitions
diff --git a/src/crwimage.cpp b/src/crwimage.cpp
index 60ce8de3..7b61aa57 100644
--- a/src/crwimage.cpp
+++ b/src/crwimage.cpp
@@ -11,20 +11,7 @@
 #include "crwimage_int.hpp"
 #include "error.hpp"
 #include "futils.hpp"
-#include "value.hpp"
 #include "tags.hpp"
-#include "tags_int.hpp"
-
-// + standard includes
-#include <iostream>
-#include <iomanip>
-#include <stack>
-#include <cstdlib>
-#include <cstring>
-#include <ctime>
-#include <cmath>
-#include <cassert>
-
 
 // *****************************************************************************
 // class member definitions
diff --git a/src/datasets.cpp b/src/datasets.cpp
index fb85b25c..e68e2073 100644
--- a/src/datasets.cpp
+++ b/src/datasets.cpp
@@ -9,11 +9,8 @@
 #include "datasets.hpp"
 #include "error.hpp"
 #include "types.hpp"
-#include "value.hpp"
-#include "metadatum.hpp"
 #include "i18n.h"                // NLS support.
 
-#include <iostream>
 #include <iomanip>
 #include <regex>
 #include <sstream>
diff --git a/src/error.cpp b/src/error.cpp
index b7386e68..df447379 100644
--- a/src/error.cpp
+++ b/src/error.cpp
@@ -2,6 +2,7 @@
 
 // included header files
 #include "error.hpp"
+#include "types.hpp"
 #include "i18n.h"                // NLS support.
 
 // + standard includes
diff --git a/src/exif.cpp b/src/exif.cpp
index 637b73eb..5217c1af 100644
--- a/src/exif.cpp
+++ b/src/exif.cpp
@@ -8,28 +8,25 @@
  */
 // *****************************************************************************
 // included header files
-#include "config.h"
-
 #include "exif.hpp"
+
+#include "basicio.hpp"
+#include "config.h"
+#include "error.hpp"
 #include "metadatum.hpp"
 #include "tags.hpp"
 #include "tags_int.hpp"
-#include "value.hpp"
-#include "types.hpp"
-#include "error.hpp"
-#include "basicio.hpp"
+#include "tiffcomposite_int.hpp"  // for Tag::root
 #include "tiffimage.hpp"
 #include "tiffimage_int.hpp"
-#include "tiffcomposite_int.hpp" // for Tag::root
+#include "types.hpp"
+#include "value.hpp"
 
 // + standard includes
-#include <iostream>
-#include <sstream>
-#include <utility>
 #include <algorithm>
-#include <cstring>
-#include <cassert>
 #include <cstdio>
+#include <iostream>
+#include <utility>
 
 // *****************************************************************************
 namespace {
diff --git a/src/fujimn_int.cpp b/src/fujimn_int.cpp
index 7821eddc..b6cd58ee 100644
--- a/src/fujimn_int.cpp
+++ b/src/fujimn_int.cpp
@@ -11,15 +11,9 @@
 #include "types.hpp"
 #include "fujimn_int.hpp"
 #include "tags_int.hpp"
-#include "value.hpp"
 #include "i18n.h"                // NLS support.
 
 // + standard includes
-#include <string>
-#include <sstream>
-#include <iomanip>
-#include <cassert>
-#include <cstring>
 
 // *****************************************************************************
 // class member definitions
diff --git a/src/futils.cpp b/src/futils.cpp
index e7334a52..438669e5 100644
--- a/src/futils.cpp
+++ b/src/futils.cpp
@@ -1,16 +1,14 @@
 // SPDX-License-Identifier: GPL-2.0-or-later
 
 // included header files
-#include "config.h"
-
 #include "futils.hpp"
-#include "datasets.hpp"
-#include "enforce.hpp"
-#include "image_int.hpp"
+
+#include "config.h"
 
 // + standard includes
 #include <algorithm>
 #include <array>
+#include <cstring>
 #include <filesystem>
 #include <sstream>
 #include <stdexcept>
diff --git a/src/gifimage.cpp b/src/gifimage.cpp
index f483355a..3bc4c797 100644
--- a/src/gifimage.cpp
+++ b/src/gifimage.cpp
@@ -1,14 +1,12 @@
 // SPDX-License-Identifier: GPL-2.0-or-later
 
 // included header files
-#include "config.h"
-
 #include "gifimage.hpp"
+
+#include "config.h"
 #include "error.hpp"
 #include "futils.hpp"
 
-#include <iostream>
-
 // *****************************************************************************
 // class member definitions
 namespace Exiv2 {
@@ -16,7 +14,7 @@ namespace Exiv2 {
     GifImage::GifImage(BasicIo::UniquePtr io)
         : Image(ImageType::gif, mdNone, std::move(io))
     {
-    } // GifImage::GifImage
+    }
 
     std::string GifImage::mimeType() const
     {
diff --git a/src/http.cpp b/src/http.cpp
index deb221f3..52b00d39 100644
--- a/src/http.cpp
+++ b/src/http.cpp
@@ -12,7 +12,6 @@
 
 #include <stdio.h>
 #include <array>
-#include <sys/stat.h>
 
 ////////////////////////////////////////
 // platform specific code
@@ -25,11 +24,8 @@
 #define  closesocket close
 
 #include <unistd.h>
-#include <strings.h>
 #include <errno.h>
 #include <sys/socket.h>
-#include <sys/un.h>
-#include <sys/uio.h>
 #include <fcntl.h>
 #include <netinet/in.h>
 #include <arpa/inet.h>
diff --git a/src/image.cpp b/src/image.cpp
index b7b3124a..bf2d17e9 100644
--- a/src/image.cpp
+++ b/src/image.cpp
@@ -1,57 +1,49 @@
 // SPDX-License-Identifier: GPL-2.0-or-later
 
 // included header files
-#include "config.h"
-
 #include "image.hpp"
-#include "image_int.hpp"
-#include "error.hpp"
+
+#include "config.h"
 #include "enforce.hpp"
+#include "error.hpp"
 #include "futils.hpp"
+#include "image_int.hpp"
 #include "safe_op.hpp"
 #include "slice.hpp"
 
-#ifdef   EXV_ENABLE_BMFF
+#ifdef EXV_ENABLE_BMFF
 #include "bmffimage.hpp"
-#endif// EXV_ENABLE_BMFF
+#endif  // EXV_ENABLE_BMFF
 #include "cr2image.hpp"
 #include "crwimage.hpp"
 #include "epsimage.hpp"
 #include "jpgimage.hpp"
 #include "mrwimage.hpp"
-#ifdef   EXV_HAVE_LIBZ
-# include "pngimage.hpp"
-#endif// EXV_HAVE_LIBZ
-#include "rafimage.hpp"
-#include "tiffimage.hpp"
-#include "tiffimage_int.hpp"
-#include "tiffcomposite_int.hpp"
-#include "tiffvisitor_int.hpp"
-#include "webpimage.hpp"
-#include "orfimage.hpp"
-#include "gifimage.hpp"
-#include "psdimage.hpp"
-#include "tgaimage.hpp"
+#ifdef EXV_HAVE_LIBZ
+#include "pngimage.hpp"
+#endif  // EXV_HAVE_LIBZ
 #include "bmpimage.hpp"
+#include "gifimage.hpp"
 #include "jp2image.hpp"
 #include "nikonmn_int.hpp"
-
-#include "rw2image.hpp"
+#include "orfimage.hpp"
 #include "pgfimage.hpp"
+#include "psdimage.hpp"
+#include "rafimage.hpp"
+#include "rw2image.hpp"
+#include "tags_int.hpp"
+#include "tgaimage.hpp"
+#include "tiffimage.hpp"
+#include "webpimage.hpp"
 #include "xmpsidecar.hpp"
 
 // + standard includes
-#include <cerrno>
+#include <cassert>
 #include <cstdio>
 #include <cstring>
-#include <cassert>
-#include <iostream>
 #include <limits>
 #include <set>
 
-#include <sys/types.h>
-#include <sys/stat.h>
-
 // *****************************************************************************
 namespace {
 
diff --git a/src/image_int.cpp b/src/image_int.cpp
index deccb560..1586a4a5 100644
--- a/src/image_int.cpp
+++ b/src/image_int.cpp
@@ -2,10 +2,12 @@
 
 #include "image_int.hpp"
 
+#include <cassert>
 #include <cstdarg>
 #include <cstddef>
-#include <cstring>
 #include <cstdio>
+#include <cstring>
+#include <vector>
 
 namespace Exiv2::Internal {
     std::string stringFormat(const char* format, ...)
diff --git a/src/image_int.hpp b/src/image_int.hpp
index 783b7476..3158b3de 100644
--- a/src/image_int.hpp
+++ b/src/image_int.hpp
@@ -5,9 +5,11 @@
 
 // *****************************************************************************
 // included header files
-#include "types.hpp"
+#include "slice.hpp"  // for Slice
 
-// + standard includes
+#include <stddef.h>   // for size_t
+#include <stdint.h>   // for int32_t
+#include <ostream>    // for ostream, basic_ostream::put
 #include <string>
 
 #if (defined(__GNUG__) || defined(__GNUC__)) || defined(__clang__)
diff --git a/src/ini.cpp b/src/ini.cpp
index 17100f17..c3527653 100755
--- a/src/ini.cpp
+++ b/src/ini.cpp
@@ -7,7 +7,6 @@
 //
 // https://github.com/benhoyt/inih
 
-#include "config.h"
 #include "ini.hpp"
 
 #include <algorithm>
@@ -18,7 +17,6 @@ using std::string;
 using namespace Exiv2;
 
 #include <stdio.h>
-#include <ctype.h>
 #include <string.h>
 
 #if !INI_USE_STACK
diff --git a/src/iptc.cpp b/src/iptc.cpp
index ceeb0450..25d93d15 100644
--- a/src/iptc.cpp
+++ b/src/iptc.cpp
@@ -2,18 +2,16 @@
 
 // included header files
 #include "iptc.hpp"
-#include "types.hpp"
-#include "error.hpp"
-#include "enforce.hpp"
-#include "value.hpp"
+
 #include "datasets.hpp"
-#include "jpgimage.hpp"
+#include "enforce.hpp"
+#include "error.hpp"
 #include "image_int.hpp"
+#include "types.hpp"
+#include "value.hpp"
 
 // + standard includes
-#include <iostream>
 #include <algorithm>
-#include <fstream>      // write the temporary file
 
 // *****************************************************************************
 namespace {
diff --git a/src/jp2image.cpp b/src/jp2image.cpp
index a9eee89c..54fbc92c 100644
--- a/src/jp2image.cpp
+++ b/src/jp2image.cpp
@@ -14,14 +14,6 @@
 #include "types.hpp"
 #include "safe_op.hpp"
 
-// + standard includes
-#include <array>
-#include <string>
-#include <cstring>
-#include <iostream>
-#include <cassert>
-#include <cstdio>
-
 // JPEG-2000 box types
 const uint32_t kJp2BoxTypeJp2Header   = 0x6a703268; // 'jp2h'
 const uint32_t kJp2BoxTypeImageHeader = 0x69686472; // 'ihdr'
diff --git a/src/jpgimage.cpp b/src/jpgimage.cpp
index ed3c4692..5edf737a 100644
--- a/src/jpgimage.cpp
+++ b/src/jpgimage.cpp
@@ -4,7 +4,6 @@
 #include "config.h"
 
 #include "jpgimage.hpp"
-#include "tiffimage.hpp"
 #include "image_int.hpp"
 #include "error.hpp"
 #include "futils.hpp"
@@ -22,14 +21,6 @@
 
 #include "fff.h"
 
-// + standard includes
-#include <algorithm>                               // for EOF
-#include <cstdio>                               // for EOF
-#include <cstring>
-#include <cassert>
-#include <stdexcept>
-#include <iostream>
-
 // *****************************************************************************
 // class member definitions
 
diff --git a/src/makernote_int.cpp b/src/makernote_int.cpp
index 0ec0cd8d..0c5ffa51 100644
--- a/src/makernote_int.cpp
+++ b/src/makernote_int.cpp
@@ -11,21 +11,18 @@
 #include "ini.hpp"
 #include "tiffcomposite_int.hpp"
 #include "tiffvisitor_int.hpp"
-#include "tiffimage.hpp"
 #include "tiffimage_int.hpp"
 #include "utils.hpp"
 
 // + standard includes
 #include <array>
 #include <filesystem>
-#include <fstream>
 #include <iostream>
 
 namespace fs = std::filesystem;
 
 #if !defined(_MSC_VER) && !defined(__MINGW__)
 #include <unistd.h>
-#include <sys/types.h>
 #include <pwd.h>
 #else
 #include <shlobj.h>
diff --git a/src/makernote_int.hpp b/src/makernote_int.hpp
index 934d7d23..fa4db63d 100644
--- a/src/makernote_int.hpp
+++ b/src/makernote_int.hpp
@@ -5,13 +5,14 @@
 
 // *****************************************************************************
 // included header files
-#include "tifffwd_int.hpp"
 #include "tags_int.hpp"
 #include "types.hpp"
 
-// *****************************************************************************
 // namespace extensions
 namespace Exiv2::Internal {
+
+    class IoWrapper;
+    class TiffComponent;
     // *****************************************************************************
     // function prototypes
     /*!
diff --git a/src/metadatum.cpp b/src/metadatum.cpp
index 7f85046f..324d6c9c 100644
--- a/src/metadatum.cpp
+++ b/src/metadatum.cpp
@@ -1,15 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0-or-later
 
-// included header files
 #include "metadatum.hpp"
 
-// + standard includes
-#include <iostream>
-#include <iomanip>
-
-
-// *****************************************************************************
-// class member definitions
 namespace Exiv2 {
 
     Key::UniquePtr Key::clone() const
diff --git a/src/minoltamn_int.cpp b/src/minoltamn_int.cpp
index f2837f84..2e549447 100644
--- a/src/minoltamn_int.cpp
+++ b/src/minoltamn_int.cpp
@@ -7,16 +7,12 @@
 #include "value.hpp"
 #include "exif.hpp"
 #include "i18n.h"                // NLS support.
-#include "datasets.hpp"
 
 #include <string>
 #include <sstream>
 #include <iomanip>
-#include <cassert>
-#include <cstring>
 
 #include <stdio.h> // popen to call exiftool
-#include <string.h>
 
 // *****************************************************************************
 // class member definitions
diff --git a/src/minoltamn_int.hpp b/src/minoltamn_int.hpp
index d20dcc9b..39da7c0b 100644
--- a/src/minoltamn_int.hpp
+++ b/src/minoltamn_int.hpp
@@ -6,10 +6,6 @@
 // *****************************************************************************
 // included header files
 #include "tags.hpp"
-#include "types.hpp"
-
-// + standard includes
-#include <iosfwd>
 
 // *****************************************************************************
 // namespace extensions
diff --git a/src/mrwimage.cpp b/src/mrwimage.cpp
index 63dfda5f..c529cb34 100644
--- a/src/mrwimage.cpp
+++ b/src/mrwimage.cpp
@@ -1,30 +1,22 @@
 // SPDX-License-Identifier: GPL-2.0-or-later
 
 // included header files
-#include "config.h"
-
 #include "mrwimage.hpp"
-#include "tiffimage.hpp"
-#include "image.hpp"
+
 #include "basicio.hpp"
-#include "error.hpp"
+#include "config.h"
 #include "enforce.hpp"
+#include "error.hpp"
 #include "futils.hpp"
+#include "image.hpp"
+#include "tiffimage.hpp"
 
-// + standard includes
-#include <string>
-#include <cstring>
-#include <iostream>
-#include <cassert>
-
-// *****************************************************************************
-// class member definitions
 namespace Exiv2 {
 
     MrwImage::MrwImage(BasicIo::UniquePtr io, bool /*create*/)
         : Image(ImageType::mrw, mdExif | mdIptc | mdXmp, std::move(io))
     {
-    } // MrwImage::MrwImage
+    }
 
     std::string MrwImage::mimeType() const
     {
diff --git a/src/nikonmn_int.cpp b/src/nikonmn_int.cpp
index 2efc1b06..128f4d33 100644
--- a/src/nikonmn_int.cpp
+++ b/src/nikonmn_int.cpp
@@ -1,24 +1,16 @@
 // SPDX-License-Identifier: GPL-2.0-or-later
 
 // included header files
-#include "types.hpp"
 #include "nikonmn_int.hpp"
-#include "value.hpp"
-#include "image.hpp"
-#include "tags_int.hpp"
+
+#include "exif.hpp"
+#include "i18n.h"  // NLS support.
 #include "makernote_int.hpp"
-#include "error.hpp"
-#include "i18n.h"                // NLS support.
+#include "tags_int.hpp"
+#include "value.hpp"
 
 // + standard includes
-#include <string>
-#include <sstream>
-#include <iomanip>
-#include <cassert>
-#include <cstring>
-#include <math.h> //for log, pow, abs
 #include <cmath>
-#include <limits>
 
 // *****************************************************************************
 // class member definitions
diff --git a/src/nikonmn_int.hpp b/src/nikonmn_int.hpp
index d79f18f9..1a16d51f 100644
--- a/src/nikonmn_int.hpp
+++ b/src/nikonmn_int.hpp
@@ -18,12 +18,6 @@
 // *****************************************************************************
 // included header files
 #include "tags.hpp"
-#include "types.hpp"
-
-// + standard includes
-#include <string>
-#include <iosfwd>
-#include <memory>
 
 // *****************************************************************************
 // namespace extensions
diff --git a/src/olympusmn_int.cpp b/src/olympusmn_int.cpp
index c04ffa04..7d4123f4 100644
--- a/src/olympusmn_int.cpp
+++ b/src/olympusmn_int.cpp
@@ -2,20 +2,13 @@
 
 // *****************************************************************************
 // included header files
-#include "types.hpp"
 #include "olympusmn_int.hpp"
-#include "value.hpp"
-#include "image.hpp"
-#include "tags_int.hpp"
-#include "makernote_int.hpp"
-#include "i18n.h"                // NLS support.
 
-// + standard includes
-#include <string>
-#include <sstream>
-#include <iomanip>
-#include <cassert>
-#include <cstring>
+#include "exif.hpp"
+#include "i18n.h"  // NLS support.
+#include "makernote_int.hpp"
+#include "tags_int.hpp"
+#include "value.hpp"
 
 // *****************************************************************************
 // class member definitions
diff --git a/src/olympusmn_int.hpp b/src/olympusmn_int.hpp
index fd1e3e24..6d1ee2d3 100644
--- a/src/olympusmn_int.hpp
+++ b/src/olympusmn_int.hpp
@@ -13,12 +13,9 @@
 // *****************************************************************************
 // included header files
 #include "tags.hpp"
-#include "types.hpp"
 
 // + standard includes
-#include <string>
 #include <iosfwd>
-#include <memory>
 
 // *****************************************************************************
 // namespace extensions
diff --git a/src/orfimage_int.hpp b/src/orfimage_int.hpp
index 9051c47e..5215b720 100644
--- a/src/orfimage_int.hpp
+++ b/src/orfimage_int.hpp
@@ -6,7 +6,6 @@
 // *****************************************************************************
 // included header files
 #include "tiffimage_int.hpp"
-#include "types.hpp"
 
 // *****************************************************************************
 // namespace extensions
diff --git a/src/panasonicmn_int.cpp b/src/panasonicmn_int.cpp
index 4d15ea14..47f80f65 100644
--- a/src/panasonicmn_int.cpp
+++ b/src/panasonicmn_int.cpp
@@ -8,11 +8,8 @@
 #include "i18n.h"                // NLS support.
 
 // + standard includes
-#include <string>
 #include <sstream>
 #include <iomanip>
-#include <cassert>
-#include <cstring>
 
 // *****************************************************************************
 // class member definitions
diff --git a/src/panasonicmn_int.hpp b/src/panasonicmn_int.hpp
index 243a198a..c7aaa080 100644
--- a/src/panasonicmn_int.hpp
+++ b/src/panasonicmn_int.hpp
@@ -6,7 +6,6 @@
 // *****************************************************************************
 // included header files
 #include "tags.hpp"
-#include "types.hpp"
 
 // *****************************************************************************
 // namespace extensions
diff --git a/src/pentaxmn_int.cpp b/src/pentaxmn_int.cpp
index e4fae83a..38dd9679 100644
--- a/src/pentaxmn_int.cpp
+++ b/src/pentaxmn_int.cpp
@@ -7,12 +7,8 @@
 #include "value.hpp"
 #include "exif.hpp"
 #include "tags.hpp"
-#include "metadatum.hpp"
 #include "i18n.h"                // NLS support.
 
-// + standard includes
-#include <string>
-
 // *****************************************************************************
 // class member definitions
 namespace Exiv2::Internal {
diff --git a/src/pgfimage.cpp b/src/pgfimage.cpp
index 2114e8cc..89eec775 100644
--- a/src/pgfimage.cpp
+++ b/src/pgfimage.cpp
@@ -1,22 +1,14 @@
 // SPDX-License-Identifier: GPL-2.0-or-later
 
 // included header files
-#include "config.h"
-
 #include "pgfimage.hpp"
-#include "image.hpp"
-#include "pngimage.hpp"
+
 #include "basicio.hpp"
+#include "config.h"
 #include "enforce.hpp"
 #include "error.hpp"
 #include "futils.hpp"
-
-// + standard includes
-#include <cstdio>                               // for EOF
-#include <string>
-#include <cstring>
-#include <iostream>
-#include <cassert>
+#include "image.hpp"
 
 // Signature from front of PGF file
 const unsigned char pgfSignature[3] = { 0x50, 0x47, 0x46 };
diff --git a/src/pngchunk_int.cpp b/src/pngchunk_int.cpp
index 53105c22..41d829c2 100644
--- a/src/pngchunk_int.cpp
+++ b/src/pngchunk_int.cpp
@@ -24,7 +24,6 @@
 #include <cstring>
 #include <iomanip>
 #include <iostream>
-#include <sstream>
 #include <string>
 
 /*
diff --git a/src/samsungmn_int.cpp b/src/samsungmn_int.cpp
index 417068f8..01472180 100644
--- a/src/samsungmn_int.cpp
+++ b/src/samsungmn_int.cpp
@@ -8,11 +8,8 @@
 #include "i18n.h"                // NLS support.
 
 // + standard includes
-#include <string>
 #include <sstream>
 #include <iomanip>
-#include <cassert>
-#include <cstring>
 
 // *****************************************************************************
 // class member definitions
diff --git a/src/samsungmn_int.hpp b/src/samsungmn_int.hpp
index d5c3879e..e2d7ffea 100644
--- a/src/samsungmn_int.hpp
+++ b/src/samsungmn_int.hpp
@@ -6,7 +6,6 @@
 // *****************************************************************************
 // included header files
 #include "tags.hpp"
-#include "types.hpp"
 
 // *****************************************************************************
 // namespace extensions
diff --git a/src/sigmamn_int.cpp b/src/sigmamn_int.cpp
index a57246ab..5220685b 100644
--- a/src/sigmamn_int.cpp
+++ b/src/sigmamn_int.cpp
@@ -10,9 +10,6 @@
 // + standard includes
 #include <string>
 #include <sstream>
-#include <iomanip>
-#include <cassert>
-#include <cstring>
 
 // *****************************************************************************
 // class member definitions
diff --git a/src/sigmamn_int.hpp b/src/sigmamn_int.hpp
index 7fe5dd23..fd979309 100644
--- a/src/sigmamn_int.hpp
+++ b/src/sigmamn_int.hpp
@@ -6,7 +6,6 @@
 // *****************************************************************************
 // included header files
 #include "tags.hpp"
-#include "types.hpp"
 
 // *****************************************************************************
 // namespace extensions
diff --git a/src/sonymn_int.cpp b/src/sonymn_int.cpp
index b7c60e46..ba54450e 100644
--- a/src/sonymn_int.cpp
+++ b/src/sonymn_int.cpp
@@ -1,21 +1,14 @@
 // SPDX-License-Identifier: GPL-2.0-or-later
 
 // included header files
-#include "types.hpp"
-#include "minoltamn_int.hpp"
 #include "sonymn_int.hpp"
-#include "tags_int.hpp"
+
+#include "exif.hpp"
+#include "i18n.h"  // NLS support.
+#include "minoltamn_int.hpp"
 #include "tiffcomposite_int.hpp"
 #include "value.hpp"
-#include "exif.hpp"
-#include "i18n.h"                // NLS support.
 
-// + standard includes
-#include <string>
-#include <sstream>
-#include <iomanip>
-#include <cassert>
-#include <cstring>
 #include <cmath>
 
 // *****************************************************************************
diff --git a/src/tiffcomposite_int.cpp b/src/tiffcomposite_int.cpp
index 6ca4e357..e192da1a 100644
--- a/src/tiffcomposite_int.cpp
+++ b/src/tiffcomposite_int.cpp
@@ -11,13 +11,6 @@
 #include "error.hpp"
 #include "enforce.hpp"
 
-// + standard includes
-#include <string>
-#include <cstring>
-#include <iostream>
-#include <iomanip>
-#include <algorithm>
-
 // *****************************************************************************
 namespace {
     //! Add \em tobe - \em curr 0x00 filler bytes if necessary
diff --git a/src/tiffimage_int.cpp b/src/tiffimage_int.cpp
index eb221adf..bd04897c 100644
--- a/src/tiffimage_int.cpp
+++ b/src/tiffimage_int.cpp
@@ -8,8 +8,6 @@
 #include "tiffvisitor_int.hpp"
 #include "i18n.h"                // NLS support.
 
-#include <iostream>
-
 // Shortcuts for the newTiffBinaryArray templates.
 #define EXV_BINARY_ARRAY(arrayCfg, arrayDef) (newTiffBinaryArray0<&arrayCfg, EXV_COUNTOF(arrayDef), arrayDef>)
 #define EXV_SIMPLE_BINARY_ARRAY(arrayCfg) (newTiffBinaryArray1<&arrayCfg>)
diff --git a/src/tiffvisitor_int.cpp b/src/tiffvisitor_int.cpp
index ddd5c5e6..bfed835d 100644
--- a/src/tiffvisitor_int.cpp
+++ b/src/tiffvisitor_int.cpp
@@ -6,24 +6,14 @@
 #include "tiffcomposite_int.hpp" // Do not change the order of these 2 includes,
 #include "tiffvisitor_int.hpp"   // see bug #487
 #include "tiffimage_int.hpp"
-#include "image_int.hpp"
 #include "makernote_int.hpp"
 #include "exif.hpp"
 #include "enforce.hpp"
 #include "iptc.hpp"
 #include "value.hpp"
-#include "image.hpp"
 #include "jpgimage.hpp"
 #include "sonymn_int.hpp"
-#include "i18n.h"             // NLS support.
 
-// + standard includes
-#include <string>
-#include <iostream>
-#include <iomanip>
-#include <cassert>
-#include <limits>
-#include <ostream>
 
 // *****************************************************************************
 namespace {