I brought home my new iPhone 4 and was amazed at the clearness of the display. Some of the icons were blurry. I thought it was just my eyes, until I read about the new app iRetiner, available in Cydia. It turns out my vision wasn’t blurry: it was the icons that have not yet been optimized for the Retina display. iRetiner not only fixes the icons, but can do all of them in one fell swoop. See the before and after screenshots to the right.
Now, this app doesn’t currently have an easy GUI. So it must be run from a terminal like MobileTerminal that runs on iOS 4.+. OpenSSH must be installed on your phone, as well as a file explorer like iFile.
Look here for a step-by-step guide.
Your eyes will thank you for it.