1. A method performed by data processing apparatus, the method comprising: receiving, from a user associated with the data processing apparatus and through a user interface presented on a display coupled to the data processing apparatus, a user input that provides an instruction to find duplicate images; in response to receiving the user input, accessing one or more image libraries stored in a storage device coupled to the data processing apparatus, wherein an image library includes one or more image files; for each accessed image library: identifying image files that have common names, generating lower resolution images of the image files that have common names, and performing bit-comparison of the lower resolution images of the image files that have common names; based on performing the bit-comparison, determining whether the image files that have common names in one or more image libraries include duplicate images; and upon determining that the image files that have common names in one or more image libraries include duplicate images, displaying in a user interface, representations of the duplicate images for one or more image libraries that include duplicate images.