You can create your own custom app icons using the images in your icon gallery and photo gallery. Your customized icons are only applied to the Home screen. The Apps screen isn't affected by your changes.
Touch and hold the icon you want to customize, then release
the icon. An editing icon appears in its upper-right corner.
Tap the icon.
Tap the image you want then tap OK.
OR
Tap Add new and select the desired size of the icon. Then choose and image from your Gallery and crop it as desired.