LOL! You weren't kidding about the unflattering pictures! Personally, i think that first picture is darling :p Its so wonky!! *smooshes the mare*
I agree with Spyder on improving the chances by breeding the mare to a -proven- producer of horses with a build well suited to Jumping =) The horse Spyder posted was a German Warmblood that is homozygous (garunteed color) so regardless it would be a quality colored foal. The mare herself seems to be a pretty good build. She looks particularly hearty for a TB, so a cross with a Warmblood (if that's an acceptable alternative to a TB, which is what your trainer wants) the resulting foal will almost certainly be a fantastic canadate for a Jumper (among other disciplines ^^).
Aaaaand... a Paint horse is a horse with color that stems from either Thoroughbred or Quarter Horse lineage. Any other breed with color is considered "pinto" which is a color, not a breed ^^ But, i am unsure of the APHA registering a TB x TB foal with color... *scratches head* I know they said one parent HAS to be APHA registered when i called them in February *strokes imaginary beard and hmmms....* You may want to call them and check it out =)
Personally, i like TB x Paint crosses. The TB side tends to.... even out... some of the problems that Paint Horses have by nature *coughFEETcough* ^^; Since Paint Horses tend to run really hearty and stocky, the lean and delicate Thoroughbred usually yields a good foal ^^
(and zomg i love paints, so don't h8 me 4 saying they have bad feet ;) i've had more experience with the BYB sorts who breed SOLELY for color and don't look at conformation)
Good luck!! =)