Yes you can!
Just make sure you put your entry in the respective topic and not all in one place - so a scan of a picture you drew and colored with pencils would go under Traditional Art, the lyrics to a Christmas carol changed to be all about Aya and Momiji go under Song Rewrite, and so on.
You can either use the forum attach feature, or upload the image on a website such as Imgur or Photobucket and link in your post.
Check out the
dedicated subforum for more information! I hope that helps!
EDIT: As an aside, if you're thinking of donating via Dwolla it takes a few days to clear and confirm your account (I'm still waiting on my end) so get on that all you silly Americans :V :V :V
EDIT EDIT: And even when you get your account cleared you have to transfer money for the first time since you're new that's another 3-5 days. In all it can easily be
ONE FULL WEEK from signup to donation, so do not procrastinate!!!!!!!!