[DavidG]

While commonly encountered, not all frames suffered that form of damage. I've had several with and without the damage. With the weight of a full tank of gas and a rear-mounted spare wheel and tire, when the rear axle bottoms out it acts as a fulcrum resulting in the frame bending downward which manifests itself in the form of an outward bulge at the top of the frame kickup. Removing the bulge is only a partial fix as the frame has been bent downward rear of the kickup and should be restored to its original height at the rear (in relation to the rest of the frame).

Unless the bulge is extreme, it wouldn't show up all that well in a photo. A better reference is to lay a straight edge along the vertical side of the frame at the kickup. If the straight edge does not touch at both of its ends, the frame is bent (bulged).