A visual pun is a pun involving an image or images (in addition to or instead of language), often based on a rebus.
Visual puns in which the image is at odds with the inscription are common in cartoons such as Lost Consonants or The Far Side as well as in Dutch gable stones. For instance the "Batenburg" stone from Prinsengracht, Amsterdam, shown here, puns on the words baten (to profit) and burg (castle) which together make up the name of a village near Nijmegen. European heraldry contains the technique of canting arms, which can be considered punning.
Examples
References
Visual pun Wikipedia(Text) CC BY-SA