[Admins]

No, it depends on the number of images. Having a lot (hundreds) of separate graphics is slow, and also updating graphics is slow (huge gifs or the whole level covered with animated flower or water tiles). So there needs to be some trade-off.
For best speed do:
- use tiles for static graphics including the background and small details that are repeated often
- use separate npcs for graphics that are supposed to move or animated or change often or should appear on top of players