+ # This only saves 0.4% on top of the above.
+ # @cmd = ("optipng", "-quiet", "-o7", $tmp);
+ # print STDERR "$progname: exec: " . join(' ', @cmd) . "\n"
+ # if ($verbose > 2);
+ # safe_system (@cmd);
+
+ if (! -s $tmp) {
+ unlink $tmp;
+ error ("failed: " . join(" ", @cmd));
+ }
+