There is noooooo way to tell from a pic like that. bears are extremely hard to feild judge weight without solid reference point to compare the bear to. Our baits are 45 gallon drums and from the height of it's back to the barrel you can get an decent idea. Even then guestimates are sometimes 50-75 lbs off!
80-90 lb cubs in that pic? Man oh man you guys must have monster bears compared to Northern Ontario.
The distance of the camera from the bear is another factor. Ever make your fish look bigger by strecthing your arm out to the camera?
You just can't guess from a pic like that without being the guy who set the bait and camera IMO.