+$supported = imagetypes();
+if( $supported & IMG_PNG ) $img_format="png";
+elseif( $supported & IMG_GIF ) $img_format="gif";
+elseif( $supported & IMG_JPG ) $img_format="jpeg";
+elseif( $supported & IMG_WBMP ) $img_format="wbmp";
+elseif( $supported & IMG_XPM ) $img_format="xpm";
+
+$cachefilename = NULL;
+