The easiest way to do this is to click on the Send to Site link and then choose what you want to send. (: Go to whichever source you want to upload on (remember, must be related to that film!) and at the top of the page in between your profile and private messages the Send to Site link is there.
Another way to send is to do it from the fan sections themselves. There's a "Send" tab at the top when you're on the page with the galleries.
Have fun!