ImageOptim - Better Save For Web

ImageOptim is lossless. There's a lossy companion app for it: http://pngmini.com

No image goes on my company's website without passing through here!

Very cool - we use a bunch of the same underlying libraries for our automated image optimization at BitBalloon (https://www.bitballoon.com)

Cool! I use it in a lots of projects...(we use it in Product Hunt too)

I use this all the time. Easy performance win. Nothing should go online without it.

its nice but i still prefer to use sips :) http://goo.gl/zjSny

I use this every single day.

Use it daily - great tool!

I just discovered it but I wish I had more upvotes to give you. I love how simple it is to use.