application bundle does not contain an icon in ICNS format

When you try to add your application to App Store make sure that your app in ICNS format.

You can create this kind of file using following application

/Developer/Applications/Utilities/Icon Composer.app

1. Open Photoshop Elements or anything else you use for editing
2. Copy image into Clipboard
3. Start Icon Composer
4. Paste Clipboard into Image Composer
5. Save image

That’s it. You are done. Now, you can add this icon into your Mac App and set it as application’t icon.