App submission failed due to icon dimensions (0 x 0)
According to this solution https://devforums.apple.com/message/612098#612098 make this steps:
- Install ApplicationLoader_2.5.1.dmg (Just install it, you don't need to launch/use it)
- Quit & restart Xcode
- Clean Project
- Archive (again)
- Validate/Submit now works
This solution fixed my problems with submission.
Tomasz's solution is fine, but there's a much simpler solution: select your Icon.png and Icon@2x.png, and in the right-hand side inspector, change File Type from "PNG" to "Icon".
After this change, you can Archive and submit your application as you normally would directly within XCode.