1. A method comprising: receiving an image of at least a part of a document; performing optical character recognition of at least the part of the image based on a physical structure; identifying, within the image, a polygonal object having a visually distinct border comprising a plurality of edges of one or more intersecting rectangles; and responsive to evaluating at least one condition associated with one or more attributes of the identified polygonal object, classifying the identified polygonal object as a screenshot image.