1. A method for data entry, comprising: receiving a plurality of images; sorting the images into an order responsive to a measure of similarity between the images, so as to group similar images together in the order; presenting to an operator a first image among the images in the order, and receiving an input from the operator specifying a code to be assigned to the first image; presenting to the operator a second image, subsequent to the first image among the images in the order, along with the code specified by the operator for assignment to the first image; and assigning the code to the second image responsive to a single input action by the operator, indicating that the second image is to be assigned the same code as the first image.