An image display apparatus includes a version detecting unit that detects a version of data about a subject, a control unit that compares at least a part of the version of the data about the subject detected by the version detecting unit with at least a part of a software version of the image display apparatus and that controls processing of the data about the subject based on whether at least the part of the version of the data about the subject is identical with at least the part of the software version, and an output unit that outputs warning information when at least the part of the version of the data about the subject is not identical with at least the part of the software version, the warning information indicating that the version of the data about the subject is not identical with the software version.
