Hi,
JoomlArt does great job in optimizing the templates and JS/CSS, but I found out the PNG files are not optimized.
I use PNGGauntlet (http://pnggauntlet.com/) to optimize the PNG files. It uses loads of lossless PNG compression algorithms and chooses the best outcome. Not a bit gets lost. A regular template uses tens of these files, and a regular Joomla website has 2000+ PNG files. I optimize the whole site before opening and save lots of disk space and bandwidth. Files get %0-%95 smaller. Sometimes even gif files get much smaller when converted to PNG and optimized, but you need to change related php and css files.
This is a tip for all users and a request for JoomlArt designers.
Bülent Özden
Harikalar Kutusu