Irayo ma versicolor
Uhm, well, don't really know which picture you mean exactly, because there is no video of the first pic (finished), but a video of the second "pic", which is still a "wip" (work in progress), so it's not finished yet
The first one took me about 2 hours to finish, but I don't really like how it came out. But well, it was my first pic of a Na'vi shortly after I watched Avatar for the first time, plus I used no reference.
The second pic so far took me about 3 hours (with pauses and stuff) to make it look like what it looks like at the end of the video (didn't continue drawing that pic yet). ^^
Hope that answers your question