Popular app SeriesGuide was pulled from the Play Store without warning yesterday, but it's already back today. As expected, the problem was the use of (technically) copyrighted content in the screenshots. The developers have rectified this by making the screenshots incredibly boring.
Instead of the promo images for all the TV series listed in SeriesGuide (which doesn't actually provide access to this content), the app now just has colored blocks. No one, as far as I'm aware, has a copyright on colored blocks. You'll obviously get the real cover art if you download the app, which is pulled from TheTVDB.
Google seems to be serious about this very rigid interpretation of copyright in screenshots. Going forward, the human review system will probably catch things like this before they go live, but at least in this case it didn't take long to fix the issue. As an alternative to blocks of color, developers of similar apps might choose to use content from sources like the Blender Foundation in screenshots.