1. A method comprising: receiving a first image at a computing device through a network; dividing the first image into a plurality of partitions by the computing device; for each partition of the first image, generating one or more min-hash sketches for the partition by the computing device; storing the generated one or more min-hash sketches for each partition of the first image by the computing device; dividing the first image into a grid of elements; determining one or more min-hashes of each element; and storing the computed one or more min-hashes of each element.