1. An image processing device comprising: a face detector configured to detect a face based on a taken image; and an output processor configured to have a function to execute privacy-mask processing for privacy protection for an image of a face detected by the face detector or an image of a background of the face, wherein the output processor includes a function to separately output an image of a face detected by the face detector and an image of a background of the face which are each subjected to or not subjected to the privacy-mask processing.