Think about what the track bar does to the axle as it moves through it's cycle. Since one end is fixed (at the frame), the other end moves in an arc (not straight up and down). Since it looks like your track bar is pretty much flat at rest (unless those pics were at full compression or something), your axle is pulled towards the driver's side when the suspension compresses (when you hit a bump), and then back to the passenger side as the suspension rebounds to normal height. Since your drag link is longer it moves in a different (larger) arc. So when you hit a bump and the track bar pulls the axle towards the driver's side, the drag link pulls the steering knuckle less to the drivers side, since it's moving in a bigger arc. This effectively turns your wheels to the passenger side, turning the vehicle right, and then back left as the suspension rebounds. This is how bump steer happens. If your track bar is at a downward angle then the directions will all be reversed, since a bump would cause the track bar to become closer to flat, and thus move the axle to the passenger side, and the drag link would move the steering knuckle less to the passenger side, causing you to turn left, but you get the idea.
Now, if your track bar is the same length as the drag link they will travel in the exact same arc. If they are at the same angle, they are in the same point in that arc, meaning when you hit a bump they both pull on their respective parts of the axle the same amount, so the steering knuckle doesn't move in relation to the axle and you don't get bump steer. It doesn't matter where the track bar is in relation to the drag link (it can be higher, lower, or further right or further left), as long as it is the same length, and at the same angle.
Make perfect sense?
