diff --git a/tools/gfx.c b/tools/gfx.c
index b1f9aebad..a3012c088 100644
--- a/tools/gfx.c
+++ b/tools/gfx.c
@@ -102,10 +102,10 @@ void trim_whitespace(struct Graphic *graphic) {
 void remove_whitespace(struct Graphic *graphic) {
 	int tile_size = Options.depth * 8;
 	if (Options.interleave) tile_size *= 2;
-    
-    // Make sure we have a whole number of tiles, round down if required
-    graphic->size &= tile_size - 1;
-    
+	
+	// Make sure we have a whole number of tiles, round down if required
+	graphic->size &= tile_size - 1;
+	
 	int i = 0;
 	for (int j = 0; i < graphic->size && j < graphic->size; i += tile_size, j += tile_size) {
 		while (j < graphic->size && is_whitespace(&graphic->data[j], tile_size)) {
@@ -140,10 +140,10 @@ void remove_duplicates(struct Graphic *graphic) {
 	int tile_size = Options.depth * 8;
 	if (Options.interleave) tile_size *= 2;
 	int num_tiles = 0;
-    
-    // Make sure we have a whole number of tiles, round down if required
-    graphic->size &= tile_size - 1;
-    
+	
+	// Make sure we have a whole number of tiles, round down if required
+	graphic->size &= tile_size - 1;
+	
 	for (int i = 0, j = 0; i < graphic->size && j < graphic->size; i += tile_size, j += tile_size) {
 		while (j < graphic->size && tile_exists(&graphic->data[j], graphic->data, tile_size, num_tiles)) {
 			if (Options.keep_whitespace && is_whitespace(&graphic->data[j], tile_size)) {
@@ -163,7 +163,7 @@ void remove_duplicates(struct Graphic *graphic) {
 }
 
 bool flip_exists(uint8_t *tile, uint8_t *tiles, int tile_size, int num_tiles, bool xflip, bool yflip) {
-	uint8_t *flip = alloca(tile_size);
+	uint8_t flip[tile_size];
 	int half_size = tile_size / 2;
 	for (int i = 0; i < tile_size; i++) {
 		int byte = i;
@@ -191,10 +191,10 @@ void remove_flip(struct Graphic *graphic, bool xflip, bool yflip) {
 	int tile_size = Options.depth * 8;
 	if (Options.interleave) tile_size *= 2;
 	int num_tiles = 0;
-    
-    // Make sure we have a whole number of tiles, round down if required
-    graphic->size &= tile_size - 1;
-    
+	
+	// Make sure we have a whole number of tiles, round down if required
+	graphic->size &= tile_size - 1;
+	
 	for (int i = 0, j = 0; i < graphic->size && j < graphic->size; i += tile_size, j += tile_size) {
 		while (j < graphic->size && flip_exists(&graphic->data[j], graphic->data, tile_size, num_tiles, xflip, yflip)) {
 			if (Options.keep_whitespace && is_whitespace(&graphic->data[j], tile_size)) {