A stationary front is depicted in the picture at L. A stationary from is a narrow zone separating two air masses in which neither air mass is displacing the other. When this occurs there is a stall in the motion of the front. The blue triangles point away from the cold air and the red semicircles point away from the warm air.
I can't see the picture, but to do the dilation you must first figure out the coordinates of the first image and then figure out what half of it is and add that on to the new image or take that much off of the new image.
