ltlC,
You have exactly the opposite problem most have when estimating fish weight. I've seen hundreds of 8-9 lb fish that were called "12-13 pounders". I mean, a 15 lb. hatchery steelhead is bigger than most people think it is. I've found that people consistently guess 2-3 lbs heavier than their fish really is.
Another thing I know is that photos lie. It's pretty difficult ot get an idea how big a fish was through a photo, unless multiple angles and lighting are used. A single photo without much reference makes it diffcult to judge size. If they actually taped it, and calculated the size with the 4/3 LxGxG / 1000 formula, I'm more likely to believe what the formula says than what the picture looks like. A pic might be worth a thousand words, but I've found that the formula doesn't lie by much, but pics sometimes do.
Last year my buddy and I caught a couple beauty hatchery fish. His outweighed mine by 2 lbs. You'd never know it in the pics.
If the problem you have is guessing 10 and winding up with 13 or 14............I'd say that's a pretty good problem to have.