Your question: [ With the tile set animation does it have to be three frames or does the amount not matter? ]
[answer:] There are 5 frames for tile set animations. These are the full tile sets, and between the 5 of them, all tiles can be the same or have those small variations that mimic animation. If not all five are set/submitted in the custom form, it defaults to the standard sprite sheet without the frame versions. If all 5 are submitted (frames 0-4), they are stored in local storage when the game is played and they are used to animate each/any tile.