She looks fine to me. Good condition too, IMO. I think that her legs and body are decently proportioned for a two year old, and that her belly is giving the illusion of them being shorter than they are.
You asked if anyone else had two year old pictures, so I'll share a few with you of our filly, although she's only 19 1/2 months old, not two. She came from a similar situation though maybe more extreme. She was extremely emaciated and at only about half of what her body weight should have been, infested with worms and lice, and very sick. As she has been recovering from all of that (she was taken from her old home late in December) there have been multiple times when her belly has looked quite bloated dispite having a clean fecal and high quality food. I think its just something they have to get through as their digestive tract heals (hers had all but stopped functioning) and regenerates itself. I actually started her on a few power doses, then a maintenance dose of ProBios for about a month and it helped with the belly quite a bit, as well as clearing up a bit of runny poo she was having. It might be an option for you, if you're interested. It doesn't cost a whole lot and can be bought in gel or powder form.
Note that Kenzie (our filly) is VERY stunted because of her neglect and only stands at 12.3hh, and she was still in horrifying condition in this photo (only about 4 weeks after coming to us) but I figured I'd share with you since the 'pot belly' look seemed similar. Since your girl is already at her ideal weight though, it could just be a growth spurt that is causing it, worms, or ulcers, or just not enough nutrience and too much 'filler.' Its hard to tell sometimes.
Still ghastly thin with a gigantic potbelly and tons of starvation hairs + winter coat.
Now, after the probios and a LOT of rehabbing, supplementation, free choice hay, etc. She's still holding on to a little bit of that belly and needs more weight but IMO it looks far better.
(she's also floppy eared, which is another story. Ignore that xD)
I'd definitely get a fecal if you can though, just to make sure it isn't worms your dealing with, and maybe look up the signs of ulcers to see if that might be something she's dealing with.
She sure is a cutie though, and thick (heavier boned) legs is a GOOD thing, especially since TBs are notorious for stick legs ;)