/vr/ - Retro Games

http://mitaki28.info/pixcaler/

Chrome-only, handles transparency but you'll need to pad out the image with a few pixels. Feed it sprite sheets, there's no size limit since it runs on your own PC.

https://github.com/mitaki28/pixcaler Github page. It appears to be trained on iPhone RPG sprites that were scaled down nearest-neighbor and works well with Final Fantasy styled sprites and tiny renders... or tiny photos, like Doom.