diff --git a/src/hardware/hw_cache.c b/src/hardware/hw_cache.c
index 02df290b8c0634382a978a32d96c075b385d2d12..5cfd0f61c52b989ccf368fe1338e2b2f856b311f 100644
--- a/src/hardware/hw_cache.c
+++ b/src/hardware/hw_cache.c
@@ -690,7 +690,9 @@ static void HWR_GenerateTexture(INT32 texnum, GLTexture_t *grtex)
 	// Composite the columns together.
 	for (i = 0, patch = texture->patches; i < texture->patchcount; i++, patch++)
 	{
+#ifndef NO_PNG_LUMPS
 		size_t lumplength = W_LumpLengthPwad(patch->wad, patch->lump);
+#endif
 		realpatch = W_CacheLumpNumPwad(patch->wad, patch->lump, PU_CACHE);
 #ifndef NO_PNG_LUMPS
 		if (R_IsLumpPNG((UINT8 *)realpatch, lumplength))
@@ -929,9 +931,9 @@ static void HWR_LoadPatchFlat(GLMipmap_t *grMipmap, lumpnum_t flatlumpnum)
 {
 	UINT8 *flat;
 	patch_t *patch = (patch_t *)W_CacheLumpNum(flatlumpnum, PU_STATIC);
+#ifndef NO_PNG_LUMPS
 	size_t lumplength = W_LumpLength(flatlumpnum);
 
-#ifndef NO_PNG_LUMPS
 	if (R_IsLumpPNG((UINT8 *)patch, lumplength))
 		patch = R_PNGToPatch((UINT8 *)patch, lumplength, NULL, false);
 #endif
diff --git a/src/r_data.c b/src/r_data.c
index 524baad151cf534125790bc125d597f7620d27c5..d37f7822d84b8e49b2ca964b33cc09869b38662f 100644
--- a/src/r_data.c
+++ b/src/r_data.c
@@ -831,7 +831,9 @@ void R_LoadTextures(void)
 		{
 			UINT16 wadnum = (UINT16)w;
 			lumpnum_t lumpnum = texstart + j;
+#ifndef NO_PNG_LUMPS
 			size_t lumplength;
+#endif
 
 			if (wadfiles[w]->type == RET_PK3)
 			{
@@ -839,8 +841,10 @@ void R_LoadTextures(void)
 					continue; // If it is then SKIP IT
 			}
 
-			lumplength = W_LumpLengthPwad(wadnum, lumpnum);
 			patchlump = W_CacheLumpNumPwad(wadnum, lumpnum, PU_CACHE);
+#ifndef NO_PNG_LUMPS
+			lumplength = W_LumpLengthPwad(wadnum, lumpnum);
+#endif
 
 			//CONS_Printf("\n\"%s\" is a single patch, dimensions %d x %d",W_CheckNameForNumPwad((UINT16)w,texstart+j),patchlump->width, patchlump->height);
 			texture = textures[i] = Z_Calloc(sizeof(texture_t) + sizeof(texpatch_t), PU_STATIC, NULL);
@@ -2798,22 +2802,23 @@ boolean R_IsLumpPNG(const UINT8 *d, size_t s)
 
 #ifdef HAVE_PNG
 
-#if PNG_LIBPNG_VER_DLLNUM < 14
+/*#if PNG_LIBPNG_VER_DLLNUM < 14
 typedef PNG_CONST png_byte *png_const_bytep;
-#endif
-typedef struct {
-	png_const_bytep buffer;
-	png_uint_32 bufsize;
-	png_uint_32 current_pos;
+#endif*/
+typedef struct
+{
+	const UINT8 *buffer;
+	UINT32 size;
+	UINT32 position;
 } png_io_t;
 
 static void PNG_IOReader(png_structp png_ptr, png_bytep data, png_size_t length)
 {
 	png_io_t *f = png_get_io_ptr(png_ptr);
-	if (length > (f->bufsize - f->current_pos))
+	if (length > (f->size - f->position))
 		png_error(png_ptr, "PNG_IOReader: buffer overrun");
-	memcpy(data, f->buffer + f->current_pos, length);
-	f->current_pos += length;
+	memcpy(data, f->buffer + f->position, length);
+	f->position += length;
 }
 
 typedef struct
@@ -2899,10 +2904,10 @@ static png_bytep *PNG_Read(const UINT8 *png, UINT16 *w, UINT16 *h, INT16 *topoff
 	png_memcpy(png_jmpbuf(png_ptr), jmpbuf, sizeof jmp_buf);
 #endif
 
-	// set our own read_function
-	png_io.buffer = (png_const_bytep)png;
-	png_io.bufsize = size;
-	png_io.current_pos = 0;
+	// set our own read function
+	png_io.buffer = png;
+	png_io.size = size;
+	png_io.position = 0;
 	png_set_read_fn(png_ptr, &png_io, PNG_IOReader);
 
 	memset(&chunk, 0x00, sizeof(png_chunk_t));
@@ -3069,10 +3074,10 @@ boolean R_PNGDimensions(UINT8 *png, INT16 *width, INT16 *height, size_t size)
 	png_memcpy(png_jmpbuf(png_ptr), jmpbuf, sizeof jmp_buf);
 #endif
 
-	// set our own read_function
-	png_io.buffer = (png_bytep)png;
-	png_io.bufsize = size;
-	png_io.current_pos = 0;
+	// set our own read function
+	png_io.buffer = png;
+	png_io.size = size;
+	png_io.position = 0;
 	png_set_read_fn(png_ptr, &png_io, PNG_IOReader);
 
 #ifdef PNG_SET_USER_LIMITS_SUPPORTED
diff --git a/src/w_wad.c b/src/w_wad.c
index 4d08b26dc03b03b0be41e4a70a23e736db5ba1ea..51c77fd8783d7439bb88b9775adb93c57546d0a3 100644
--- a/src/w_wad.c
+++ b/src/w_wad.c
@@ -1531,7 +1531,10 @@ void *W_CachePatchNumPwad(UINT16 wad, UINT16 lump, INT32 tag)
 		if (!lumpcache[lump])
 		{
 			size_t len = W_LumpLengthPwad(wad, lump);
-			void *ptr, *lumpdata, *srcdata = NULL;
+			void *ptr, *lumpdata;
+#ifndef NO_PNG_LUMPS
+			void *srcdata = NULL;
+#endif
 
 			ptr = Z_Malloc(len, tag, &lumpcache[lump]);
 			lumpdata = Z_Malloc(len, tag, NULL);