1. A processing apparatus comprising: a processor; and a memory storing instructions, the instructions, when executed by the processor, causing the processing apparatus to perform: receiving read image data, which is image data generated by reading an object with an image reading apparatus; extracting a target image, which is an image having a part indicating the object, from a read image that is an image indicated by the read image data; and generating output data, which indicates a synthesis image in which the target image and a template image are synthesized, wherein the template image has an assignment area to which the target image is assigned, and wherein the generating comprises arranging two or more of the same target images on the assignment area.