It sure looks like double hight.
Compare my sig to a sleeping slig in game. It's not half as thick as the ripped sprite is, and then the rest of the sprites should be the same. I tried to scale an abe up, even though he looks the right size. double hight sounds like he will be ultra-stretched, but he wont. He just getts a little taller.
Try it, I think they are deffinately two two times taller.
Edit: Here is my proof: The left abe is the one directly from the bmp.zip and the right one is the same but scaled up to double hight. He looks really different than u could imagine after scaling 
It has to be the size!
compare him to the button.