today i went down to the lake and caught about a 4lb bass. but it almost looked like a spot but ive never caught a spot before in the lake and i caught it on an 8 1/2 inch worm cuz yall post some pics w/ the difference. this fishes belly was very white and FAT. saw a guy catch a 7 1/2 lber bout 10 mins later (black bass)

I dont know if you can recall, but spots have sand paper like tounges, which is a dead giveaway. Heres a comparison. Im far from an expert, ive never even caught a spot, but this is the only difference i notice, which is the dotted lines along their side/belly. An expert might give you more differences

Typically spotted bass have more pronounced lines and spots, a patch on their tongue, and their jaw line does not extend pass their eye.

The tongue is a good indication, but I doubt you got a picture of that.  You can tell by the mouth as well.  Close the fish's mouth and the jaw of the spot will not go further back than the eyes.  You may not have a picture of the fish with his mouth closed either.  One thing you may be able to tell from a picture is the dorsal fin.  I believe this top fin on the spots is clearly connected, whereas the largemouth's appear to be two separate fins.

-J