I thought that you had an AVI, MOV, or MPG file. It looks like you have a DVD. That's a bit more complicated.
First, I do not know what the copyright restrictions are on a Disney Photomovie DVD, so I cannot speak to the legality or ethics of any action taken on one. Assuming that you have a valid copyright to take the actions you suggest, here is how I would do it.
First, you need some software to convert the DVD into a video file. I suggest something like Super (search on Super Video Converter). You will need that to create an AVI, MPG, or MOV file. Once you have that file, upload it to a video hosting site like YouTube.