So back in October I had a project called png-massacre that I never released because I never actually finished it. Over the holidays I took a hiatus from programming and just in these past couple of weeks have I started up again. It's not nearly complete, but I figured I'd push it to github under a new name, pngz, as I continue work. If you're interested in learning more, check out this article: http://heyimalex.com/journal/png-optimization