diff --git a/include/gdi.h b/include/gdi.h
index 41322afb..03c12af8 100644
--- a/include/gdi.h
+++ b/include/gdi.h
@@ -5585,7 +5585,7 @@ MG_EXPORT HICON GUIAPI LoadBitmapIconFromFile (HDC hdc,
         const char* file_name);
 
 /**
- * \fn HICON GUIAPI LoadBitmapIconFromMem (HDC hdc, const void* mem, int size,
+ * \fn HICON GUIAPI LoadBitmapIconFromMem (HDC hdc, const void* mem, size_t size,
  *      const char* ext)
  * \brief Loads an icon from memory.
  *
@@ -5602,7 +5602,7 @@ MG_EXPORT HICON GUIAPI LoadBitmapIconFromFile (HDC hdc,
  * \sa LoadBitmapIconEx
  */
 MG_EXPORT HICON GUIAPI LoadBitmapIconFromMem (HDC hdc,
-        const void* mem, int size, const char* ext);
+        const void* mem, size_t size, const char* ext);
 
 /**
  * \fn BOOL GUIAPI DestroyIcon (HICON hicon)
@@ -11211,13 +11211,13 @@ MG_EXPORT int GUIAPI LoadBitmapFromFile (HDC hdc, PBITMAP pBitmap,
 
 /**
  * \fn int GUIAPI LoadBitmapFromMem (HDC hdc, PBITMAP pBitmap, \
-                const void* mem, int size, const char* ext)
+                const void* mem, size_t size, const char* ext)
  * \brief Loads a device-dependent bitmap from memory.
  *
  * \sa LoadBitmapEx
  */
 MG_EXPORT int GUIAPI LoadBitmapFromMem (HDC hdc, PBITMAP pBitmap,
-                const void* mem, int size, const char* ext);
+                const void* mem, size_t size, const char* ext);
 
 /**
  * \fn void GUIAPI UnloadBitmap (PBITMAP pBitmap)
@@ -11387,7 +11387,7 @@ MG_EXPORT int GUIAPI LoadMyBitmapFromFile (PMYBITMAP my_bmp, RGB* pal,
 
 /**
  * \fn int GUIAPI LoadMyBitmapFromMem (PMYBITMAP my_bmp, RGB* pal, \
-                const void* mem, int size, const char* ext)
+                const void* mem, size_t size, const char* ext)
  * \brief Loads a MYBITMAP object from memory.
  *
  * This function loads a MYBITMAP object from memory.
@@ -11401,7 +11401,7 @@ MG_EXPORT int GUIAPI LoadMyBitmapFromFile (PMYBITMAP my_bmp, RGB* pal,
  * \sa LoadMyBitmapEx, MYBITMAP
  */
 MG_EXPORT int GUIAPI LoadMyBitmapFromMem (PMYBITMAP my_bmp, RGB* pal,
-                const void* mem, int size, const char* ext);
+                const void* mem, size_t size, const char* ext);
 
 /**
  * \fn void GUIAPI UnloadMyBitmap (PMYBITMAP my_bmp)
@@ -11827,7 +11827,7 @@ MG_EXPORT int GUIAPI PaintImageFromFile (HDC hdc, int x, int y,
 
 /**
  * \fn int GUIAPI PaintImageFromMem (HDC hdc, int x, int y, \
-                const void* mem, int size, const char* ext);
+                const void* mem, size_t size, const char* ext);
  * \brief Paints an image from memory on device directly.
  *
  * \param hdc The device context.
@@ -11842,7 +11842,7 @@ MG_EXPORT int GUIAPI PaintImageFromFile (HDC hdc, int x, int y,
  * \sa PaintImageEx
  */
 MG_EXPORT int GUIAPI PaintImageFromMem (HDC hdc, int x, int y,
-                const void* mem, int size, const char* ext);
+                const void* mem, size_t size, const char* ext);
 
 /**
  * \fn int GUIAPI StretchPaintImageEx (HDC hdc, int x, int y, int w, int h, \
@@ -11899,7 +11899,7 @@ MG_EXPORT int GUIAPI StretchPaintImageFromFile (HDC hdc, int x, int y,
 
 /**
  * \fn int GUIAPI StretchPaintImageFromMem (HDC hdc, int x, int y, \
- *               int w, int h, const void* mem, int size, const char* ext)
+ *               int w, int h, const void* mem, size_t size, const char* ext)
  * \brief Paints an image from memory on device directly.
  *
  * \param hdc The device context.
@@ -11916,7 +11916,7 @@ MG_EXPORT int GUIAPI StretchPaintImageFromFile (HDC hdc, int x, int y,
  * \sa StretchPaintImageEx
  */
 MG_EXPORT int GUIAPI StretchPaintImageFromMem (HDC hdc, int x, int y,
-                int w, int h, const void* mem, int size, const char* ext);
+                int w, int h, const void* mem, size_t size, const char* ext);
 
 #ifdef _MGHAVE_FIXED_MATH
 
diff --git a/include/window.h b/include/window.h
index b983a987..3225886c 100644
--- a/include/window.h
+++ b/include/window.h
@@ -5968,7 +5968,7 @@ typedef DWORD RES_KEY;
 typedef struct _INNER_RES {
     RES_KEY key;
     const Uint8* data;
-    int data_len;
+    size_t data_len;
 
     /* A special param recognized by the TYPE_OPS; normally is NULL.
      * If the data is a raw png, jpeg, bmp file content,
@@ -6051,7 +6051,7 @@ enum emResType {
 /* the return value of LoadResource with type RES_TYPE_MEM_RES */
 typedef struct _MEM_RES {
     Uint8 *data;
-    int data_len;
+    size_t data_len;
 } MEM_RES;
 
 typedef struct _FONT_RES {
diff --git a/src/mybmp/mybmp.c b/src/mybmp/mybmp.c
index 4e610c43..b2386c05 100644
--- a/src/mybmp/mybmp.c
+++ b/src/mybmp/mybmp.c
@@ -316,7 +316,7 @@ int GUIAPI LoadMyBitmapFromFile (PMYBITMAP my_bmp, RGB* pal, const char* file_na
 }
 
 int GUIAPI LoadMyBitmapFromMem (PMYBITMAP my_bmp, RGB* pal, const void* mem,
-                                int size, const char* ext)
+                                size_t size, const char* ext)
 {
     MG_RWops* area;
     int ret_val;
diff --git a/src/newgdi/icon.c b/src/newgdi/icon.c
index 2005961c..c2cc2b73 100644
--- a/src/newgdi/icon.c
+++ b/src/newgdi/icon.c
@@ -579,7 +579,7 @@ HICON GUIAPI LoadBitmapIconFromFile (HDC hdc, const char* file_name)
     return ico;
 }
 
-HICON GUIAPI LoadBitmapIconFromMem (HDC hdc, const void* mem, int size,
+HICON GUIAPI LoadBitmapIconFromMem (HDC hdc, const void* mem, size_t size,
         const char* ext)
 {
     PICON ico;
diff --git a/src/newgdi/readbmp.c b/src/newgdi/readbmp.c
index aa8ce775..bced47af 100644
--- a/src/newgdi/readbmp.c
+++ b/src/newgdi/readbmp.c
@@ -562,8 +562,8 @@ int GUIAPI LoadBitmapFromFile (HDC hdc, PBITMAP bmp, const char* file_name)
     return ret;
 }
 
-int GUIAPI LoadBitmapFromMem (HDC hdc, PBITMAP bmp, const void* mem, int size,
-                              const char* ext)
+int GUIAPI LoadBitmapFromMem (HDC hdc, PBITMAP bmp,
+        const void* mem, size_t size, const char* ext)
 {
     int ret;
     MG_RWops* area;
@@ -713,8 +713,8 @@ int GUIAPI PaintImageFromFile (HDC hdc, int x, int y, const char *file_name)
     return ret;
 }
 
-int GUIAPI PaintImageFromMem (HDC hdc, int x, int y, const void* mem,
-                int size, const char *ext)
+int GUIAPI PaintImageFromMem (HDC hdc, int x, int y,
+        const void* mem, size_t size, const char *ext)
 {
     int ret;
     MG_RWops* area;
@@ -1056,7 +1056,7 @@ int GUIAPI StretchPaintImageFromFile (HDC hdc, int x, int y, int w, int h,
 }
 
 int GUIAPI StretchPaintImageFromMem (HDC hdc, int x, int y, int w, int h,
-                const void* mem, int size, const char *ext)
+        const void* mem, size_t size, const char *ext)
 {
     int ret;
     MG_RWops* area;