Have you gotten an odd complaint message about image transparency for your decidedly non-transparent top-shelf image? Do this:

1. Open the file in Preview.
2. Choose File > Export
3. Select PNG
4. Uncheck Alpha
5. Save

This creates an RGB  version vs the original RGBA version. Use Finder’s Get Info to view the difference.

Replace your old image with the new one and Xcode stops complaining.