How do I change iPhone app icons without jailbreaking?

You can change the home screen icons for third-party (non-Apple) applications on your iPhone without jailbreaking your device. To switch icons to the photo of your choice follow these instructions:

1. Install iPhone Explorer on your computer. The program is free and comes in Windows and Mac versions.

2. Run iPhone Explorer and connect your iPhone to the computer with your USB cable.

3. In the iPhone Explorer navigation window, click the name of your iPhone to open subdirectories. Now navigate to Apps -> appname -> appname.app (replacing appname with the name of the app icon you wish to modify).

4. On the iPhone 4, rename the file icon@2x.png (or Icon@2x.png) to something else like icon@2x_bak.png. On older iPhones, rename the file icon.png (or Icon.png) to something else like icon_bak.png.

5. Create your new icon with Photoshop or another image editing program on your computer. Icons for the iPhone 4 should be sized at 114x114 pixels for the Retina display. Older iPhones will use icons sized at 57x57 pixels. All icon files must be saved as a PNG with no layers, no transparency and 72 ppi.

6. Drag the new icon into the appname.app folder opened in step 3. Rename the new file to match the name of the old icon (icon@2x.png or icon.png).

7. On your computer, exit iPhone Explorer then reboot your iPhone. The app icon you changed will appear on the home screen.