Agree with upnover's excellent post, but I have a couple of additions.
I consider a horse that jumps with this form bordline dangerous because of the hanging front end. The only thing that keeps me from saying she is absolutely dangerous is the overjumping with the body and her clear willingness and "want to." I would not jump her any higher than is pictured here; I would not jump her over any solid obstacles until her form improves dramatically. Besides working a lot on gymnastics, PLEASE learn to use groundlines to help your horse. Some of the fences pictured have no ground line, those that have one at all have it rolled directly under the fence where it simply doesn't serve its intended purpose.
A ground line should be rolled out from the base of the fence at lease 1/2 the height of the fence; in your mare's case, I would roll it out a little more. A horse that is not tidy with its front end often benefits from a longer spot/longer arc over the fence; it gives them a little more time to roll their shoulder and bring their forearm up. If you study your photos, you'll see clearly the closer to the fence she takes off, the worse she hangs. Help her take off at a more appropriate spot by using groundlines correctly.
There are some good books out there about building gymnastics and grids; you might find them helpful in designing exercises for her.