I've found that two views of the pants to be very helpful/indicative of the cut: 1) full length view, folded like you're going to put them in a clip hanger (I don't know how to describe it accurately, but it would follow the crease of the trousers, if any.) Since you know the waist size, it's easy to see if the line of the trousers is tapered (usually slim fitting) or straight (full). 2) full length again, but this time folded like a pair of jeans. Lay trousers out flat so pockets are on the left right, fly is facing you, seat behind (no pun intended). Fold along the fly, folding the waistband in half so the two pockets are face/face. Smooth everything out and lay flat. In this view, the fit of the seat (butt, thigh area) can be determined. A large curve (like a "J") in the crotch along is usually full fitting, less curve = less area/less material, slim fitting. Both are somewhat difficult to visualize in words so I suggest trying it out with some of your own pants to get the idea if you haven't already
. I've found the above two views extremely useful with jeans - by folding them as above I can usually tell if the fit will appeal to me without even trying them on. Another thing I've found helpful is to visualize in terms of pattern pieces, if you can see the seams in a photo it's the perfect way to know whether something will fit or not. This is also helpful for any alterations that may need to be done.