Well, I don't have one of these boards, but I agree it sure is confusing.

If you look at this page for the TK20-series:

http://www.clark-model.com/eng/prod_rx20/index.html

They show:



But if you look at this TK22 Tutorial:

http://www.clark-model.com/eng/prod_rx20_tu/index.html

They show:



So it looks to me like:
1) There is a difference between the TK20-series page board and the TK22-series page board.
2) The jumper is in the same location, but a different jumper designation (J2 on the TK20, J3 on the TK22).

So I would be confused trying to figure out where to put the jumper. I probably would have ignored the picture and gone by the jumper designation. If the instructions said jumper J2, then I would jumper J2 as designated on the board, rather than what the instructions show.

Steve