I had the same problem - so I'm confirming iCloud (now at version 3.1) causes error "No Error" uploading ANY picture file.
Uninstalled iCloud, problem solved.
This happens only with CoolVL, other viewers tested weren't affected by Apple's bug.
So, untill the bug is fixed, and in case you need to upload textures, either uninstall iCloud or use any viewer except CoolVL.
Thank you nofu nagy!