Your Gelding looks right for his size, assuming he is 15-16 hands, appaloosa? 1200-1300 lbs He could lose a few "extra" pounds, and use some physical exercise. I would put him in a grazing muzzle and leave it on. He will only eat the top of the grass, and not the roots, the roots hae parasites from poop and feces in the ground. Also Take him out for a daily ride for 30 minutes, trotting will help him lose the extra pounds. But overall he is beautifully built(:
Your mare look like she could lose a little weight, just work her good for 30 minutes a day also, if not more. But she looks about 14-15 hands a good weight size for her, she just has some extra weight.