Images won't show on iPad Mini compatibility mode

I'm developing an iOS app. More specifically, an iPhone and iPod Touch app, since it is not universal. Everything works fine in all 3 screens: non-retina, 3.5" retina and 4" retina.

The problem is: some images won't show up when running the app on an iPad Mini on compatibility mode. I double-checked and made sure I do have both RankingCell.png and RankingCell@2x.png in my folder, as well as in my project. Before this major bug, I had a minor one: in other area of the app, the background image of a UITableViewCell would sometimes show up a little bit dislocated to the left. None of those behaviors happen when the app runs on the Simulator, and I tried all the three available hardwares.

Is there any reason why these images are not showing up in the iPad Mini?

Screenshot for further reference:

Just found out the problem. It was mainly stupidity of mine: All the RankingCell images were actually .jpg, but named as RankingCell.png.

The reason why this was only occurring in the iPad Mini is because the older images were being loaded from cache on the other devices I tested, for I had ran the app on them before. Unlike the iPad, which had a fresh install. I could reproduce the glitch removing the app from my iPhone and then building it again.

Didn't even know this was possible. And since I was seeing the images thumbnails alright, I never suspected of such thing.