FAQ - Aperture
Users have the option to download images as a .PSD (Photoshop) file with the mask on a separate layer. This is useful for images that require specialized and more robust editing. Simply choose .PSD from the dropdown menu before downloading. Images can also be downloaded as JPEG(Joint Photographic Experts Group) or PNG(Portable Network Graphics). This choice can be made when users are in the Export section of the editing steps.
As a note: Images can only be downloaded once a mask has been approved by a user. There is not a way to download "raw images" at this time.