Image processing algorithms
I know of two semi-related trends that may be of interest (so this would be an extra answer to your question, but not the answer).

First, some progress has been made recently on the problem known as "Affine Image Matching", given two images A and B, how much an affine transformation can make A look like B (see 10.1007/978-3-642-13509-5_2 which proves that Affine Image Matching is uniform-TC0 complete).

Second, there has been studies of image transformations in the context of weighted automata.  A weighted automaton, which weights a word by an element of a semiring, describes fractal like images (intuitively, because of the loops of the automaton).  Nonetheless, actual algorithms have been invented to compress real-world pictures in weighted automata; a rational (weighted) transduction on such representations is then an image transformation.  See Chapter 11 of the Hanbook of Weighted Automata or the older Chapter 10, Volume 3 of the Hanbook of Formal Languages.