The following information is derived from the plugin description.

Adds support to compare image files.

An image that is added to the comparison behaves like a single page document containing this image. It is supported to set a zip file containing multiple images as input. The zip file behaves like a document containing each of the images.

This allows to e.g. compare a scanned document against an original PDF. Supported image formats are: PNG, JPEG, GIF and BMP.