An information processing system includes an image output unit, an image reception unit, and a determination unit. The image output unit outputs an image to a document to include first and second images. The first image includes at least one of a character and a symbol which represent at least part of a pair of an attribute name and an attribute value which are included in electronic data. The second image includes a first information image representing at least part of the attribute value, or a second information image representing a storage location of the electronic data. The image reception unit receives the output image of the document and an image of a paper document. The determination unit determines as to whether or not allowing the image of the paper document to be registered.