Hi Jan W.
To the best of my knowledge, there are no photos.
Think of it this way.....
when you tack, you must carve the board up into the wind, keeping as much power in the rig for as long as you can, being careful not to oversheet and stall the rig.
You are going to come out of the footstraps, and move forward some on the board, that is a given.
What I am suggesting, and what works for me, is to not come forward any sooner or any further than you need to step over the mast (the sail is raked all the way back until the foot of the sail is pretty much resting on the tail of the board) to avoid coming all the way forward up to the mast foot.
This allows the board to continue to carve and plane up into the wind, and then simply take your front foot and place it on the other side of the board so that momentarily you are facing the back of the board with one foot on one side of the rig, and the other foot on the other side of the rig.
Then pivot around so both feet are on the new windward side and move back, drop your weight on the rig and begin to sheet into bring the nose off the wind.
By doing this, you weight stays further aft (back toward the tail) on the board and your weight never gets forward of about 12-18" (0.3-0.5 m) behind the mast foot.
The further you move your weight forward, the more you sink the nose and the more the board slows down.
If you don't understand my english, ask some more questions and we can work through this.
Hope this helps,