significantly reduce file sizes, but uses more memory and time.
https://rt.cpan.org/Ticket/Display.html?id=94292
- - the autolevels filter now works on the luminosity of the image
+ - the autolevels filter now works on the luminance of the image
rather then working per channel. The old autolevels filter is
still available as "autolevels_skew".
https://rt.cpan.org/Ticket/Display.html?id=94413