I know you didn't ask for tack critique, but your tie-down is both too tight and unsafe--you need to use a breastcollar to run the strap through. Does he even really need the tie-down in the first place, though? Looks like a quiet, agreeable guy. And the saddle, as others have said, does not fit.
In terms of conformation, adequate although just the tiniest bit ewed neck, nice enough shoulder, fine front legs. Longer, weaker back and he's lacking condition. I'd love to see him put on just a hair of weight and gain a bunch of muscle along his topline. Steep croup, weak rear, straight through stifles and thus lacking impulsion. Perfectly suitable for trail-riding, though.