I am loading a lot of images with:
var data = NSData.FromUrl (NSUrl.FromString(url));
var img = UIImage.LoadFromData(data);
Then I cache the images to a folder and make sure this folder is purged every 7 days.
But I see there is also a "Caches/'app package name'/fsCachedData" folder with all the images. This doesn't seem to be cleared in the simulator at least. Should I clear this as well? Is there any way to prevent it from caching images here? Or is it safe to delete the folder myself?
We are seeing this in one of our apps as well. According to this link, its an iOS 8 bug which Apple will have corrected in the iOS 8.1 update today.
So to answer your question: No, you shouldn't have to delete the cache yourself and with some luck Apple's fix really will clean up the old data. If for some reason not, you should be able to delete it yourself without any problems.
[Edit] I've verified that iOS 8.1 does indeed correct the issue. The user must launch the app once after update for the cache to be cleared however.