I got mine from "My Virtual Model."
I did it 3 times; once at my start weight, once at my first goal weight, and the next at my final weight.
I have to take screen captures of each, paste them into MS Paint, save it, then open them all in Photoshop and merge them.
Someone else may have a faster/easier way to do it.
I'm actually thinking on doing one in Sims 3 tonight when I get home; that way, I can really customize it to almost exactly how I look