Most of us are pretty bad at remembering names, and developers are no different. Recalling names for all sorts of images isn’t easy, so make them more obvious by using the naming conventions in the following table. If you hire a designer, pass this list onto her and request that she use it. Also, if your app has similar images, such as weather icons, be sure to prefix those as well.

Filename Example Usage
btn- btn-back.png All button images
tab- tab-home.png All tab bar images
bkg- bkg-main.png All background images
-up btn-facebook-up.png Inactive state buttons
-down btn-facebook-down.png Active state buttons
-hover btn-facebook-hover.png Hover state buttons
@2x [email protected] This is the standard suffix required for all retina display graphics.