Based on one that I caught back in 2012, I'd guess between 6 3/4 and 7 1/4#
Stick, 7 1/4 was my guess but like I said I've never caught a LMB that big so I went with Cecil's expert opinion...she's a fat pig no doubt about that.
Not sure if I'm anymore expert than anyone else here as I'm sure some of you guys that fish in bass tournaments have handled more bass than I have.
That said, pictures can make fish look both bigger AND smaller so I figure we should opt on the high end of the scale.
I've also found photos can change the coloration of a fish depending on the lighting, background, or if a flash is used.