Importer: Archive option?

Hi
If I import new images one can activate the "archive" option. What does that mean? Is each image converted into a proprietary format and the original image is stored or not - if "archive" is activated or not?
Best Regards, Frank
If I import new images one can activate the "archive" option. What does that mean? Is each image converted into a proprietary format and the original image is stored or not - if "archive" is activated or not?
Best Regards, Frank