1. A system, comprising: one or more processors; and a memory coupled to the one or more processors and storing program instructions executable by the one or more processors to implement: dividing an input image into a plurality of patches in accordance with a regular grid; performing a patch-based image editing operation on the input image to produce an output image, wherein said performing comprises assigning a given one of the plurality of patches to a respective node of the output image; producing a refined output image, wherein said producing a refined output image comprises assigning one of a previously generated set of candidate patches to the respective node of the output image, wherein the previously generated set of candidate patches comprises the given patch and one or more jittered versions of the given patch, and wherein each of the one or more jittered versions of the given patch comprises a version of the given patch that has been shifted by a respective number of pixels in one or more directions; and outputting data representing the refined output image.