11. A computer storage medium encoding computer executable instructions that when executed by one or more processors, cause the one or more processors to perform operations comprising: supplementing an image with metadata that identifies an object in the image; providing the metadata with the image when the image is rendered so that at least a portion of the image depicting the object is interactive, in order to enable a user to enter a selection input that corresponds to the object; and performing an action in response to detecting the selection input that corresponds to the object depicted in the image.
17. The computer storage medium of claim 11 , further comprising instructions for storing the metadata in a header of a file of the image.