This folder is for adding your own custom sprites. 
The game will replace the generated sprites by the ones in this folder when the custom sprites option is activated in-game.

Over 1,300 custom sprites made by the community are included with the game. You can find even more in this google drive.
https://drive.google.com/drive/u/0/folders/0Bx5WTzAX8jMnTE45NWJFRVVNUTQ

The sprites included here have had minimal quality control, so please report any sprites that are either broken, obscene, or of the wrong Pokmon in the Discord channel.
https://discord.gg/p8xXNpu

If you want to know who made a specific sprite, ask in the Discord!