Short answer:
user pfp: 1:1: 250px x 250px
character cover: 1:1.4: 250px x 350px
all profile banners: 16:9: ~1920px x 1080px*
*Banner crop changes depending on screen size
PLEASE COMPRESS AS MUCH AS POSSIBLE - these aren’t auto compressed right now.
User profile banners are also used for vgen.co directory right now.
Note that gifs and animated webp / apng are supported for all.