Tracking content blocks in a source storage for inclusion in an image backup of the source storage. In one example embodiment, a method for tracking content blocks in a source storage for inclusion in an image backup of the source storage may include identifying files in a source storage for inclusion in image backups of the source storage, tracking, in an inclusion map and prior to a first snapshot time, locations in the source storage of content blocks of the identified files, tracking, in the inclusion map and prior to the first snapshot time, modifications to the locations in the source storage of the content blocks, taking a snapshot of the source storage at the first snapshot time, and backing up, subsequent to the first snapshot time, the content blocks tracked in the inclusion map from the snapshot into a full image backup.