Upload and size images?

[MrMonday]

Hi, I'm a refugee from trying to play wargames on roll20. My friends and I play Clan War, an old out of print samurai wargame set in the L5R universe. None of the stock models have any sort of samurai feel to them, which is fine. But is it possible for me to upload my own photoshopped tokens to this system somehow? And if so, how? Any help would be greatly appreciated, I miss playing my samurai.