Have notice a couple times that when you delete frames from a animation that video memory usage go up and stay up, this is a very serious problem and can eat over hundreds of MB of extra video memory in large projects, if you won't pay attention to it.
I always have my custom debug screen on, to see how much extra video memory every new animation cost, that's how I notice this. I was deleting frames from a animation to save extra memory, but the opposite happens:
-Deleted 6 of 10 frames in a animation that where each (218/256 pix) and my video memory went from 86.33 to 100.99mb and just we talking now about one object/animation, I try to reduce video memory to remove images but C3 add video memory usage??? Exporting the game gave same video memory usage.
Also you at Scirra should be able to reproduce this bug youre self, else I'm able to create a video from before and after.
And NO, I won't report a BUG report because of the bad experience in the 9 years with reporting bugs plus my project is to big and has copyrights in it!
Hope for a positive response because this is scary stuff to keep going with c3 when this won't get solved,
Edit: I'm using the desktop build C3 148 stable.
Edit: Maybe this helps you to solve, the C3 Stable before 148 was able to fix the video memory issues when restarting C3, but won't do it with C3 148 stable!