I am trying to optimize the graphics on my app but I don't know what the resolution of the images should be. I have the images sized at 280 X 280. The button size I have set on the control panel is 140. When I run the app, the button image is not crisp. For this button size, what should the ___X___ be?

make sure you look at the dpi (or ppi) as well. If you are developing with standard computer display values (72), it will not look near as good as the mobile's display (326 for retina).

If you have Photoshop try this (must work in other programmes too) : For this example, your file is called button1.png Open your original image at 280px Go to - edit - image size - change dpi to 326 - image height and width back to 280 px Save as [email protected] (retina version) Then Change only the dpi to 163 dpi (326 x 50%) Photoshop with auto change width,height to 140...cool Save as bouton1.png (this is the non retina version) In BT control panel set button to button1.png at width 140px Now you should have both versions crisp in your app. Nota: the @2x tells iOS to show the Retina version of your button1.png only on Retina screens. You don't have to do anything else. Edit : run results in imageoptim software, it will reduce file size with out losing quality http://imageoptim.com/