It depends sometimes on what is on the character sheet and what is not. For the most part, it is usually finding the image first with a vague idea of what the character is or is supposed to be if an image is required. Usually sections such as what gender they are, name, age, species, job and so on are already filled out by that point. History and personality are filled out after finding the picture to use in my case, but it can depend  on mood.