Memory warning and crashes, but no leaks-Collection of common programming errors

I’m creating an app based on storyboard, where each of the views has quite a lot of large images. The app crashes (not a lot, it usually crashes after 10-15 minutes of intensive use) after having displayed a few memory warning. I’ve checked instruments, and it’s not reporting any single memory leak. Also, the allocation seems to be reasonable (I’ve only got 1 or 2 peaks in the game when I load some very xib containing very big images – around 8mo for the iPad retina version). I don’t really have any objects I can release when I receive a memory warning, as all the stuff from the previous view has already been deallocated.

I’ve seen that similar problem, but it seems to be related to a specific line of code, which is not my case : iOS – App crashing after Memory Warning – Instruments showing no leaks

Is there a way to force xcode to clean the images that are cached? Otherwise, what can I do to prevent these crashes?

Thanks for your help !