Last modified: 2010-05-15 15:28:23 UTC
Thumbnails of PNGs look awful. (need better rescaling algorithm?)
You're probably using GD's awful scaling; try installing ImageMagick, then set $wgUseImageMagick = true and
$wgImageMagickConvertCommand to the full path to the 'convert' executable.
If that's not the problem, please reopen and provide more information.