Danny is having issues running Adobe Photoshop Elements 10 on his MacBook with Retina display. The icons look pixelated. Leo says that is a common issue with the Retina display when using an older version of an app. Apple deliberately makes the display larger and at half the resolution so he can see what he's looking at. He'll get the full resolution for videos and images, however.
Danny can force it to show at full resolution in the display settings, but then the text becomes really small. Also, the older program may not understand the display. He can also use third party software called SwitchResX, QuickRes, or Retina Display Menu. The cost is $0 to $5, and he probably won't find it on the App store. He'll have to search around.