A method (100) of marking an image comprising image data and associated metadata, for modification detection, is disclosed. The method (100) encodes the image data to produce encoded image data and hashes the encoded image data to provide a first hash. The first hash is added to the associated metadata to form augmented metadata the associated metadata is hashed to provide a second hash. The second hash is added to the augmented metadata. An association is created between the encoded image data, the first and second hash, and the augmented metadata, thereby marking the image.