Using the contest image as a "clone source," I painted the plant with the Mosaic Tool in Painter X.
step 2 of 3
I then varied the size of the mosaic "tiles," and painted in the background.
step 3 of 3
When the tiling was complete, I placed the contest image on top, changed the blending mode to Linear Burn, and reduced the opacity to 47% to allow the contest image to add color to the "grout" between the tiles.