I'm uploading PNGs into my gallery. They are 8-bit with 256 colours. They look fine but when I generate thumbnails and other custom image sizes, they look awful. If I download the small image files and open them in Photoshop the colour palette is down from 256 to something like 150 colours.
I think this is the piece of code in the core which creates the resized PNG and sets the number of colours;
// convert from full colors to index colors, like original PNG. if ( IMAGETYPE_PNG == $orig_type && function_exists('imageistruecolor') && !imageistruecolor( $image ) ) imagetruecolortopalette( $newimage, false, imagecolorstotal( $image ) );
Any help would be appreciated.