From the Q&A
What about resizing?
- A: sprite is allowed to be resized for as long as it doesn't add any new detail. If you have a sprite file that is 32*32 and want to use it to cover the entire screen then you can and it will still only take up 1 sprite slot. However, the moment you add more detail to this sprite it will count as combining sprites. Look at the question above for more information on that.