Is your problem that you have to add multiple copies of the same frame to an animation, thus making it big, or that the memory footprint simply grows when the animation is left playing?

In the first case, you should probably create an image cache, loading each file only once and then passing the resulting Tk image objects to the animation object, multiple times if needed.

In the second case, I assume you aren't creating new animation objects over and over but rather resetting it and re-playing the same animation object, right? If that's the case it could be a Tk bug, try destroying the animation object and creating it again from the frames after it's played each time.