Image of the changes
If you only want to save changes made since the last imaging, select Image of the changes as method in the imaging options as. This will allow you to create an image that saves only those changes that have occurred since the last base image.
O&O DiskImage compares each sector of the existing image with the corresponding sector of the imaged (source) disk while creating an image of the changes. This might take up some more time than a complete image. The image of the changes takes up much less space than a complete image.
Note: If you want to create an image of the changes, you must have created at least one complete image of each drive of interest, which will serve as base image. Afterwards, the image of the changes that you created can also serve as a new base image.
Note: The option Use checksums to administer unchanged data is always set by default. The last incremental/differential image created is enough to serve as the base image when creating an Image of the changes. If Use checksums to administer unchanged data is not set, you will need the last base image and all existing incremental images because these must be accessed as part of the imaging process.