PixelRendr: Investigate storing images as .gifs

[JoshuaKGoldberg]

Smaller 2d sprites can be stored very efficiently in the current PixelRendr format... but larger sprites, particularly those in Pokemon, tend to have a lot of data. Following or alongside #210, it'd be good to do an investigation into when base64-encoded gifs are actually more efficient as sprites.

I think a good future might be to:

• Add logic to PixelRendr to have it be able to parse .gifs using built-in browser image APIs
• Have whatever package (SpriteMakr?) creates sprites from images create whichever sprite is smaller in byte size

However, this'll also need investigating whether the parse times of base64 gifs are different in real time. Maybe they're much better than PixelRendr sprites? Maybe they're much better?