1. A method comprising: by one or more computing devices, generating a large hash value based on a first image and a content-aware hashing function, wherein the large hash value comprises a first number of dimensions; by one or more computing devices, generating a small hash value based on the large hash value and a locality-sensitive hashing function, wherein the small hash value comprises a second number of dimensions; by one or more computing devices, determining a coordinate system comprising: a plurality of buckets; and the second number of dimensions, by one or more computing devices, determining one or more buckets of the plurality of buckets, wherein the one or more buckets are adjacent to the small hash value; and by one or more computing devices, determining whether the first image is similar to one or more other images, wherein the determination is based at least on whether there are any cluster centers associated with the one or more buckets, wherein each cluster center is associated with at least one other image.