- bail out if screen resolution does not match PPM dimensions.

Previously a 640x480 PPM on an e.g. 720x400 console would just segfault when
  reading the lines. While this bug should perhaps be fixed to handle such cases
  properly we just exit gracefully until somebody is willing to take care of it
  properly.

miscutils/fbsplash.c

@@ -257,7 +257,9 @@ static void fb_drawimage(void)
 
 	if (ENABLE_FEATURE_CLEAN_UP)
 		free(head);
-
+	if (width != G.scr_var.xres || height != G.scr_var.yres)
+		bb_error_msg_and_die("PPM %dx%d does not match screen %dx%d",
+							 width, height, G.scr_var.xres, G.scr_var.yres);
 	line_size = width*3;
 	if (width > G.scr_var.xres)
 		width = G.scr_var.xres;