This is regarding errors while running a build on Xcode 8 with ARKit. So I ran into this problem and found an easy solution. When placing images in .png, jpeg, or really any other file format, my build would get rejected.
Solution: Drag your file into a browser and Save Page As.... It should work now.
Huh? I've never had a problem with PNG files being used in any Xcode project.
>wont allow build with png, jpeg files built/designed from computer.
Which computer? What OS?