When the film first came out (and I didnt know this site existed) I made scads of manipulations for friends and myself using Photoshop elements 2.0 (for those who don't know, that is an ancient program) and an Intuous 2 Tablet that I still use regularly. I recently got a copy of CS4, and after reading through this thread, Im stoked about doing a few more of these, and improving on my last pics.
I think the big things to remember about the proportional differences between Humans and Na'vi/Avatar bodies (and most common mistakes) are the ear placement and eye shape. And, of course, making the stripes look natural, with organic shapes and not TOO much darker than the surrounding skin.
Just my two cents
