You're right, he's fat.
He doesn't have the best head. It's a little coarse and blocky for an Arab, but he's a gelding and you don't ride the head.
He has a lovely shoulder, and a nice, short, sturdy back. He also has rather prominent withers for an Arab.
Not crazy about his croup, but a steeper croup means he's able to get his back end under him more than an Arab with a flat croup.
Can't really tell anything about his legs, since you don't have any front or back shots. Looks to have decent legs and feet from what I can see, and he has good pastern angles.
All in all, he's a cute little guy. What discipline do you do with him?