I've been trying to figure this out for ages; but does anyone know the criteria for a custom full body image? I know that a portrait must be around 200*200 (7.2*7.2 cm), but I can't find anything for Full-body images. Thanks in advance for any advice.

I don't think that part of the customerization is working yet since I did some in-game messing around on my part. Trying to upload an image for full body load it into portrait instead, and dropping a png file directly into 'bodies' folder doesn't make the image appear in customize menu either. Not sure it's a bug in current build, or the dev team haven't fully implemented the feature yet.

800*400