Eleven ways of flipping and mirroring the picture, all built from one operation: reading a coordinate backwards.
The three flips apply it outright. Flip horizontally and the whole picture is reversed left to right.
The eight mirror modes apply it only on one side of the midline, which is the more interesting behaviour. Mirror left to right and the left half of the picture is kept and reflected onto the right, so the result is symmetrical and half the original is discarded. Which half survives is what distinguishes the modes from each other.
The four combined modes do this on both axes at once, keeping a single quarter of the picture and repeating it four ways. That is the kaleidoscope arrangement, and it is a quick way to make a symmetrical figure out of any source at all.