DF Studio generates JPEG previews for any image file uploaded to the system. These previews are used for display within the DF Studio interface, and are compressed and optimized for viewing in a web browser. The original file is not modified in any way, unless the user chooses to delete that file from the system.
For more information about the types of previews generated by DF Studio, see Dimensions of DF Studio Preview Files.
The compression quality can be configured on a per-account basis for Enterprise and Unlimited accounts. These settings are not controllable from the user interface; adjustments are performed upon request by DF Studio support. Changes applied to quality/compression levels are not retroactive to existing previews.
For every image file, a full-sized JPEG preview is created from the uploaded file. Some image editing applications such as Lightroom, Photo Mechanic, and Aperture allow additional control over the size of the file being uploaded.