Unretiner is a very useful tool for iOS art production. I found it’s much more convenient than shrinking and resaving image from Photoshop (I often forgot to resize the shrinked image back!)

A tool for iOS developers to easily resize their @2x or -hd cocos2d images in seconds! Great for testing out non retina devices before the big painful export from Photoshop.

It’s available to download from Mac Appstore: http://itunes.apple.com/us/app/unretiner/id411277085?mt=12

And it’s also open source: https://github.com/stuartkhall/Unretiner

I would recommend it to everyone who have to work with both HD & SD resolution of iPhone / iPad.