diff --git a/examples/anim_util.c b/examples/anim_util.c
index 870e8842..b76f2d7c 100644
--- a/examples/anim_util.c
+++ b/examples/anim_util.c
@@ -688,7 +688,7 @@ int ReadAnimatedImage(const char filename[], AnimatedImage* const image,
   WebPDataInit(&webp_data);
   memset(image, 0, sizeof(*image));
 
-  if (!ExUtilReadFile(filename, &webp_data.bytes, &webp_data.size)) {
+  if (!ImgIoUtilReadFile(filename, &webp_data.bytes, &webp_data.size)) {
     fprintf(stderr, "Error reading file: %s\n", filename);
     return 0;
   }
diff --git a/examples/cwebp.c b/examples/cwebp.c
index 04619b7b..26203616 100644
--- a/examples/cwebp.c
+++ b/examples/cwebp.c
@@ -60,12 +60,12 @@ static int ReadYUV(const uint8_t* const data, size_t data_size,
 
   pic->use_argb = 0;
   if (!WebPPictureAlloc(pic)) return 0;
-  ExUtilCopyPlane(data, pic->width, pic->y, pic->y_stride,
-                  pic->width, pic->height);
-  ExUtilCopyPlane(data + y_plane_size, uv_width,
-                  pic->u, pic->uv_stride, uv_width, uv_height);
-  ExUtilCopyPlane(data + y_plane_size + uv_plane_size, uv_width,
-                  pic->v, pic->uv_stride, uv_width, uv_height);
+  ImgIoUtilCopyPlane(data, pic->width, pic->y, pic->y_stride,
+                     pic->width, pic->height);
+  ImgIoUtilCopyPlane(data + y_plane_size, uv_width,
+                     pic->u, pic->uv_stride, uv_width, uv_height);
+  ImgIoUtilCopyPlane(data + y_plane_size + uv_plane_size, uv_width,
+                     pic->v, pic->uv_stride, uv_width, uv_height);
   return use_argb ? WebPPictureYUVAToARGB(pic) : 1;
 }
 
@@ -77,13 +77,13 @@ static int ReadPicture(const char* const filename, WebPPicture* const pic,
   const uint8_t* data = NULL;
   size_t data_size = 0;
   if (pic->width != 0 && pic->height != 0) {
-    ok = ExUtilReadFile(filename, &data, &data_size);
+    ok = ImgIoUtilReadFile(filename, &data, &data_size);
     ok = ok && ReadYUV(data, data_size, pic);
   } else {
     // If no size specified, try to decode it using WIC.
     ok = ReadPictureWithWIC(filename, pic, keep_alpha, metadata);
     if (!ok) {
-      ok = ExUtilReadFile(filename, &data, &data_size);
+      ok = ImgIoUtilReadFile(filename, &data, &data_size);
       ok = ok && ReadWebP(data, data_size, pic, keep_alpha, metadata);
     }
   }
@@ -102,7 +102,7 @@ static int ReadPicture(const char* const filename, WebPPicture* const pic,
   size_t data_size = 0;
   int ok = 0;
 
-  ok = ExUtilReadFile(filename, &data, &data_size);
+  ok = ImgIoUtilReadFile(filename, &data, &data_size);
   if (!ok) goto End;
 
   if (pic->width == 0 || pic->height == 0) {
@@ -958,7 +958,7 @@ int main(int argc, const char *argv[]) {
   // Open the output
   if (out_file != NULL) {
     const int use_stdout = !strcmp(out_file, "-");
-    out = use_stdout ? ExUtilSetBinaryMode(stdout) : fopen(out_file, "wb");
+    out = use_stdout ? ImgIoUtilSetBinaryMode(stdout) : fopen(out_file, "wb");
     if (out == NULL) {
       fprintf(stderr, "Error! Cannot open output file '%s'\n", out_file);
       goto Error;
diff --git a/examples/dwebp.c b/examples/dwebp.c
index 4e94c037..22e21a2b 100644
--- a/examples/dwebp.c
+++ b/examples/dwebp.c
@@ -505,7 +505,7 @@ static int SaveOutput(const WebPDecBuffer* const buffer,
 #endif
 
   if (needs_open_file) {
-    fout = use_stdout ? ExUtilSetBinaryMode(stdout) : fopen(out_file, "wb");
+    fout = use_stdout ? ImgIoUtilSetBinaryMode(stdout) : fopen(out_file, "wb");
     if (fout == NULL) {
       fprintf(stderr, "Error opening output file %s\n", out_file);
       return 0;
diff --git a/examples/gif2webp.c b/examples/gif2webp.c
index ca6623dd..75fe075e 100644
--- a/examples/gif2webp.c
+++ b/examples/gif2webp.c
@@ -500,7 +500,7 @@ int main(int argc, const char *argv[]) {
   }
 
   if (out_file != NULL) {
-    if (!ExUtilWriteFile(out_file, webp_data.bytes, webp_data.size)) {
+    if (!ImgIoUtilWriteFile(out_file, webp_data.bytes, webp_data.size)) {
       fprintf(stderr, "Error writing output file: %s\n", out_file);
       goto End;
     }
diff --git a/examples/vwebp.c b/examples/vwebp.c
index 980adca4..00267e6b 100644
--- a/examples/vwebp.c
+++ b/examples/vwebp.c
@@ -469,8 +469,8 @@ int main(int argc, char *argv[]) {
     return 0;
   }
 
-  if (!ExUtilReadFile(kParams.file_name,
-                      &kParams.data.bytes, &kParams.data.size)) {
+  if (!ImgIoUtilReadFile(kParams.file_name,
+                         &kParams.data.bytes, &kParams.data.size)) {
     goto Error;
   }
 
diff --git a/examples/webpmux.c b/examples/webpmux.c
index 58cfebaa..5495d016 100644
--- a/examples/webpmux.c
+++ b/examples/webpmux.c
@@ -369,7 +369,7 @@ static int ReadFileToWebPData(const char* const filename,
                               WebPData* const webp_data) {
   const uint8_t* data;
   size_t size;
-  if (!ExUtilReadFile(filename, &data, &size)) return 0;
+  if (!ImgIoUtilReadFile(filename, &data, &size)) return 0;
   webp_data->bytes = data;
   webp_data->size = size;
   return 1;
@@ -389,7 +389,7 @@ static int CreateMux(const char* const filename, WebPMux** mux) {
 static int WriteData(const char* filename, const WebPData* const webpdata) {
   int ok = 0;
   FILE* fout = strcmp(filename, "-") ? fopen(filename, "wb")
-                                     : ExUtilSetBinaryMode(stdout);
+                                     : ImgIoUtilSetBinaryMode(stdout);
   if (fout == NULL) {
     fprintf(stderr, "Error opening output WebP file %s!\n", filename);
     return 0;
diff --git a/extras/get_disto.c b/extras/get_disto.c
index 755e5af9..a834e4d7 100644
--- a/extras/get_disto.c
+++ b/extras/get_disto.c
@@ -31,7 +31,7 @@ static size_t ReadPicture(const char* const filename, WebPPicture* const pic,
   const uint8_t* data = NULL;
   size_t data_size = 0;
   WebPImageReader reader = NULL;
-  int ok = ExUtilReadFile(filename, &data, &data_size);
+  int ok = ImgIoUtilReadFile(filename, &data, &data_size);
   if (!ok) goto Error;
 
   pic->use_argb = 1;  // force ARGB
diff --git a/extras/webp_quality.c b/extras/webp_quality.c
index 92aa51e3..69fc8223 100644
--- a/extras/webp_quality.c
+++ b/extras/webp_quality.c
@@ -29,7 +29,7 @@ int main(int argc, const char *argv[]) {
       const uint8_t* data = NULL;
       size_t data_size = 0;
       int q;
-      const int ok = ExUtilReadFile(filename, &data, &data_size);
+      const int ok = ImgIoUtilReadFile(filename, &data, &data_size);
       if (!ok) continue;
       q = VP8EstimateQuality(data, data_size);
       if (!quiet) printf("[%s] ", filename);
diff --git a/imageio/imageio_util.c b/imageio/imageio_util.c
index 82ac65a5..b3ec287f 100644
--- a/imageio/imageio_util.c
+++ b/imageio/imageio_util.c
@@ -22,7 +22,7 @@
 // -----------------------------------------------------------------------------
 // File I/O
 
-FILE* ExUtilSetBinaryMode(FILE* file) {
+FILE* ImgIoUtilSetBinaryMode(FILE* file) {
 #if defined(_WIN32)
   if (_setmode(_fileno(file), _O_BINARY) == -1) {
     fprintf(stderr, "Failed to reopen file in O_BINARY mode.\n");
@@ -32,7 +32,7 @@ FILE* ExUtilSetBinaryMode(FILE* file) {
   return file;
 }
 
-int ExUtilReadFromStdin(const uint8_t** data, size_t* data_size) {
+int ImgIoUtilReadFromStdin(const uint8_t** data, size_t* data_size) {
   static const size_t kBlockSize = 16384;  // default initial size
   size_t max_size = 0;
   size_t size = 0;
@@ -42,7 +42,7 @@ int ExUtilReadFromStdin(const uint8_t** data, size_t* data_size) {
   *data = NULL;
   *data_size = 0;
 
-  if (!ExUtilSetBinaryMode(stdin)) return 0;
+  if (!ImgIoUtilSetBinaryMode(stdin)) return 0;
 
   while (!feof(stdin)) {
     // We double the buffer size each time and read as much as possible.
@@ -65,15 +65,15 @@ int ExUtilReadFromStdin(const uint8_t** data, size_t* data_size) {
   return 0;
 }
 
-int ExUtilReadFile(const char* const file_name,
-                   const uint8_t** data, size_t* data_size) {
+int ImgIoUtilReadFile(const char* const file_name,
+                      const uint8_t** data, size_t* data_size) {
   int ok;
   void* file_data;
   size_t file_size;
   FILE* in;
   const int from_stdin = (file_name == NULL) || !strcmp(file_name, "-");
 
-  if (from_stdin) return ExUtilReadFromStdin(data, data_size);
+  if (from_stdin) return ImgIoUtilReadFromStdin(data, data_size);
 
   if (data == NULL || data_size == NULL) return 0;
   *data = NULL;
@@ -103,8 +103,8 @@ int ExUtilReadFile(const char* const file_name,
   return 1;
 }
 
-int ExUtilWriteFile(const char* const file_name,
-                    const uint8_t* data, size_t data_size) {
+int ImgIoUtilWriteFile(const char* const file_name,
+                       const uint8_t* data, size_t data_size) {
   int ok;
   FILE* out;
   const int to_stdout = (file_name == NULL) || !strcmp(file_name, "-");
@@ -124,8 +124,8 @@ int ExUtilWriteFile(const char* const file_name,
 
 // -----------------------------------------------------------------------------
 
-void ExUtilCopyPlane(const uint8_t* src, int src_stride,
-                     uint8_t* dst, int dst_stride, int width, int height) {
+void ImgIoUtilCopyPlane(const uint8_t* src, int src_stride,
+                        uint8_t* dst, int dst_stride, int width, int height) {
   while (height-- > 0) {
     memcpy(dst, src, width * sizeof(*dst));
     src += src_stride;
diff --git a/imageio/imageio_util.h b/imageio/imageio_util.h
index c3ad6a4c..f97de69b 100644
--- a/imageio/imageio_util.h
+++ b/imageio/imageio_util.h
@@ -25,29 +25,29 @@ extern "C" {
 
 // Reopen file in binary (O_BINARY) mode.
 // Returns 'file' on success, NULL otherwise.
-FILE* ExUtilSetBinaryMode(FILE* file);
+FILE* ImgIoUtilSetBinaryMode(FILE* file);
 
 // Allocates storage for entire file 'file_name' and returns contents and size
 // in 'data' and 'data_size'. Returns 1 on success, 0 otherwise. '*data' should
 // be deleted using free().
 // If 'file_name' is NULL or equal to "-", input is read from stdin by calling
-// the function ExUtilReadFromStdin().
-int ExUtilReadFile(const char* const file_name,
-                   const uint8_t** data, size_t* data_size);
+// the function ImgIoUtilReadFromStdin().
+int ImgIoUtilReadFile(const char* const file_name,
+                      const uint8_t** data, size_t* data_size);
 
-// Same as ExUtilReadFile(), but reads until EOF from stdin instead.
-int ExUtilReadFromStdin(const uint8_t** data, size_t* data_size);
+// Same as ImgIoUtilReadFile(), but reads until EOF from stdin instead.
+int ImgIoUtilReadFromStdin(const uint8_t** data, size_t* data_size);
 
 // Write a data segment into a file named 'file_name'. Returns true if ok.
 // If 'file_name' is NULL or equal to "-", output is written to stdout.
-int ExUtilWriteFile(const char* const file_name,
-                    const uint8_t* data, size_t data_size);
+int ImgIoUtilWriteFile(const char* const file_name,
+                       const uint8_t* data, size_t data_size);
 
 //------------------------------------------------------------------------------
 
 // Copy width x height pixels from 'src' to 'dst' honoring the strides.
-void ExUtilCopyPlane(const uint8_t* src, int src_stride,
-                     uint8_t* dst, int dst_stride, int width, int height);
+void ImgIoUtilCopyPlane(const uint8_t* src, int src_stride,
+                        uint8_t* dst, int dst_stride, int width, int height);
 
 #ifdef __cplusplus
 }    // extern "C"
diff --git a/imageio/webpdec.c b/imageio/webpdec.c
index 22753227..4e335f6e 100644
--- a/imageio/webpdec.c
+++ b/imageio/webpdec.c
@@ -51,7 +51,7 @@ int ExUtilLoadWebP(const char* const in_file,
                    WebPBitstreamFeatures* bitstream) {
   VP8StatusCode status;
   WebPBitstreamFeatures local_features;
-  if (!ExUtilReadFile(in_file, data, data_size)) return 0;
+  if (!ImgIoUtilReadFile(in_file, data, data_size)) return 0;
 
   if (bitstream == NULL) {
     bitstream = &local_features;
@@ -184,15 +184,15 @@ int ReadWebP(const uint8_t* const data, size_t data_size,
           const WebPYUVABuffer* const yuva = &output_buffer->u.YUVA;
           const int uv_width = (pic->width + 1) >> 1;
           const int uv_height = (pic->height + 1) >> 1;
-          ExUtilCopyPlane(yuva->y, yuva->y_stride,
-                          pic->y, pic->y_stride, pic->width, pic->height);
-          ExUtilCopyPlane(yuva->u, yuva->u_stride,
-                          pic->u, pic->uv_stride, uv_width, uv_height);
-          ExUtilCopyPlane(yuva->v, yuva->v_stride,
-                          pic->v, pic->uv_stride, uv_width, uv_height);
+          ImgIoUtilCopyPlane(yuva->y, yuva->y_stride,
+                             pic->y, pic->y_stride, pic->width, pic->height);
+          ImgIoUtilCopyPlane(yuva->u, yuva->u_stride,
+                             pic->u, pic->uv_stride, uv_width, uv_height);
+          ImgIoUtilCopyPlane(yuva->v, yuva->v_stride,
+                             pic->v, pic->uv_stride, uv_width, uv_height);
           if (has_alpha) {
-            ExUtilCopyPlane(yuva->a, yuva->a_stride,
-                            pic->a, pic->a_stride, pic->width, pic->height);
+            ImgIoUtilCopyPlane(yuva->a, yuva->a_stride,
+                               pic->a, pic->a_stride, pic->width, pic->height);
           }
         }
       }
diff --git a/imageio/wicdec.c b/imageio/wicdec.c
index 94ac1b83..b7ed7c3c 100644
--- a/imageio/wicdec.c
+++ b/imageio/wicdec.c
@@ -88,7 +88,7 @@ static HRESULT OpenInputStream(const char* filename, IStream** stream) {
   if (!strcmp(filename, "-")) {
     const uint8_t* data = NULL;
     size_t data_size = 0;
-    const int ok = ExUtilReadFile(filename, &data, &data_size);
+    const int ok = ImgIoUtilReadFile(filename, &data, &data_size);
     if (ok) {
       HGLOBAL image = GlobalAlloc(GMEM_MOVEABLE, data_size);
       if (image != NULL) {