Methods, apparatus, and computer-readable storage media for patch-based image synthesis. A patch matching technique provides an extended patch search space that encompasses geometric and photometric transformations, as well as gradient domain features. The geometric transformations may include translation, rotation, reflection, scale, and non-uniform scale. The photometric transformations may include gain and bias. Patch-based image synthesis techniques may leverage the extended patch search space in various image synthesis applications. The patch-based image synthesis techniques may also integrate image gradients into the patch representation and replace conventional color averaging with a technique that performs voting for colors and gradients and then solves a screened Poisson equation based on values for colors and gradients when blending patch(es) with a target image.