You can use this forum to request character image edits. This means making already existing characters that you found somewhere, like from an anime, look like one of the 8 Post-Eophrim races. All you need to do is link the original and then detail what you want to have edited, like the race, color changes and so on. Remember, however, that the harder the edit is, the less likely it is that someone will do it.
If you want to take an edit request on, just reply to the topic and ask the requester if they are okay with it. This is done to avoid multiple people working on the same request without noticing.
You can also use this forum to give away edits you made. Don't forget to remove them if someone takes them.