PNGPress is a frontend for OptiPNG. It takes one or more image files and squeezes every last kb out of them, without "losing" any data. Just drag your images onto the PNGPress icon, and away it goes. PNGPress will also backup your original images, and allows you to set the compression level yourself.
PNGPress 1.1.3 is available in this handy 401kb Zip file, and runs on Intel Macs with OS 10.6+ (Snow Leopard), Intel only.
If you have a problem or request for future versions of PNGPress, .
If you find this application has value, I'd love for you to throw me some cash (paypal) so I can keep making things like this. It's not easy being an independent developer in 2009. I'm also available for freelance work.