diff --git a/src/image.c b/src/image.c
index 8013009..618ccbd 100644
--- a/src/image.c
+++ b/src/image.c
@@ -108,8 +108,8 @@ static inline void buf_read(uint8_t *buf,
                             size_t x, size_t y, size_t stride,
                             uint8_t *r, uint8_t *g, uint8_t *b,
                             int depth) {
-    *r = buf[depth*stride*y + depth*x],
-    *g = buf[depth*stride*y + depth*x + 1],
+    *r = buf[depth*stride*y + depth*x];
+    *g = buf[depth*stride*y + depth*x + 1];
     *b = buf[depth*stride*y + depth*x + 2];
 }
 
@@ -274,14 +274,14 @@ error_open:
     return NULL;
 }
 
-static cammy_image *load_png(const char *file) {
+static cammy_image *load_stb(const char *file) {
     uint8_t *buf;
     cammy_image *image;
     cammy_image_format format = CAMMY_IMAGE_NONE;
 
     int width, height, channels;
 
-    if ((buf = stbi_load(file, &width, &height, &channels, 4)) == NULL) {
+    if ((buf = stbi_load(file, &width, &height, &channels, 0)) == NULL) {
         goto error_stbi_load;
     }
 
@@ -340,12 +340,10 @@ cammy_image *cammy_image_open(const char *file) {
 
     close(fd);
 
-    if (memcmp(buf, CAMMY_IMAGE_MAGIC_PNG, sizeof(buf)) == 0) {
-        loader = load_png;
-    } else if (memcmp(buf, CAMMY_IMAGE_MAGIC_TILE, sizeof(buf)) == 0) {
+    if (memcmp(buf, CAMMY_IMAGE_MAGIC_TILE, sizeof(buf)) == 0) {
         loader = load_tile;
     } else {
-        goto error_invalid_format;
+        loader = load_stb;
     }
 
     return loader(file);
@@ -354,7 +352,6 @@ error_read:
 error_lseek:
     close(fd);
 
-error_invalid_format:
 error_open:
     return NULL;
 }
@@ -523,7 +520,8 @@ static void copy_buf(cammy_image *dest,
                      cammy_image_region *from) {
     size_t x, y;
 
-    int channels = format_channels(dest->format);
+    int channels_dest = format_channels(dest->format),
+        channels_src  = format_channels(src->format);
 
     for (y=0; y < from->height; y++) {
         if (to->y + y > dest->height) {
@@ -540,17 +538,18 @@ static void copy_buf(cammy_image *dest,
             buf_read(src->buf,
                      from->x + x,
                      from->y + y,
-                     from->width,
-                     &r, &g, &b, channels);
+                     src->width,
+                     &r, &g, &b, channels_src);
 
             buf_write(dest->buf,
                       to->x + x,
                       to->y + y,
                       dest->width,
-                      r, g, b, channels);
+                      r, g, b, channels_dest);
         }
     }
 }
+
 static void copy_rgb_to_2bpp_tile(cammy_image *dest,
                                   cammy_image *src,
                                   cammy_image_point *to,