Me, I would open up the characters folder and look for it.
Or, when choosing what character the event should be, check the name.
Or you're using the name of the character sprite file in the game, calling it and then using it, for whatever, reason, and while it would be script support-ish, I'd feel that this thread should thus be in the script request board.
Or you're looking for a sprite on the internet, thus this would be a resource request.