Various embodiments include automatically selecting and modifying objects within an image that are similar to an object previously selected by a user. A user first selects an object in a displayed image. Object feature descriptors are generated describing a shape formed by edges of the object, and image feature descriptors are generated describing shapes formed by edges automatically detected in the image. The object feature descriptors are compared with the image feature descriptors to automatically identify other objects in the image having edges similar to the selected object. The pixels of the user selected object and the automatically identified objects are modified according to a user specified function.