A random compare thing.
Differences I see
-Jaguars spine is slightly upwards curving, leopards runs upwards slightly between shoulders and hips but is pretty straight.
-Jaguars belly is hangs more, the leopard is pulling in more, like she's trying not to look fat. The jaguar also has loose skin on its belly whereas the leopard doesn't, not sure how well i showed this.
-Different marking though similar in that small spots on head and lower legs, large spots on rest of legs and neck and rosettes on body, both have broken collar markings on neck. Tail markings different, leopards tail is much longer.
-Jaguar is generally more stocky.
-Jaguar has a broader head, stronger jaw, more underbite, more definition between forehead and muzzle, rounder ears than leopard.
These are only what I see so please add in comments if you see more.