$text = <$tmpfile>;
# Use pngcrush to rewrite the image file with the new text.
-system("pngcrush", "-fix", "-rem", "text", "-text", "b",
+system("pngcrush", "-fix", "-oldtimestamp", "-rem", "text", "-text", "b",
$key, $text, $infile, $tmpfile);
if (0 == $? >> 8) {
not $outfile and $outfile = $infile;