1. An information processing device comprising: a memory configured to store a history of performing, on an image having an attribute, a process that conceals an area within the image; and at least one hardware processor configured to implement: a receiving unit that receives a first image; a decision unit that extracts from the memory a history of a process performed on a second image, which is different from the first image, having an attribute that matches an attribute of the received first image, and on the basis of the extracted history of a process, decides a concealment area within the received first image; and a concealment unit that conceals the concealment area within the first image decided by the decision unit.