--- src/mesa/main/image.c	2006-11-16 09:40:38.000000000 +0800
+++ src/mesa/main/image.c.new	2006-11-16 09:40:27.000000000 +0800
@@ -4173,7 +4173,7 @@
    if (width <= 0 || height <= 0 || depth <= 0)
       return NULL;  /* generate error later */
 
-   if (format == GL_BITMAP) {
+   if (type == GL_BITMAP) {
       bytesPerRow = (width + 7) >> 3;
       flipBytes = !unpack->LsbFirst;
       swap2 = swap4 = GL_FALSE;