Whoa, that thing looks huge. But its impossible to get a good estimate based on that photo. One of the things I look at when judging photos is the size of the maxillary bone in relation to the anglers hand. I know people have different sized hands, but the hand and bone are always in perspective to each other regardless of how far out the angler is holding fish. That bone is very big compared to the anglers hand, and IMHO that is a very big bass. My guess is at leat 13 pounds.