This Script-Fu script automatically generates all the required and recommend app icons with the proper names and resolutions for the various iOS devices from a single source image.
For each app icon: the source image* is duplicated, then the duplicated image is scaled, then the scaled duplicate image is exported to a .png file, and finally the scaled duplicate image is deleted. The resulting .png files have the proper names and resolutions for iOS app icons for iPad and iPhone/iPod touch for both normal and retina displays.
*The recommended resolution of the source image is 1024 x 1024
This script is also located at: https://github.com/m2orris/GIMP-scripts
This script contains two functions.
File -->Export as iOS --> Icons for Device(s) ...
iTunesArtwork@2x (1024 x 1024)
iTunesArtwork (512 x 512)
Iconfirstname.lastname@example.org (144 x 144)
Icon@2x.png (114 x 114)
Icon-72.png (72 x 72)
Icon.png (57 x 57)
Icon-Smallemail@example.com (100 x 100)
Icon-Small-50.png (50 x 50)
Icon-Small@2x.png (58 x 58)
Icon-Small.png (29 x 29)
File --> Export as iOS --> Image(s) ...