Photoshop's naming scheme was initially based on version numbers. However, in October 2004, following the introduction of Creative Suite branding, each new version of Photoshop was designated with "CS" plus a number; e.g., the eighth major version of Photoshop was Photoshop CS and the ninth major version was Photoshop CS2. Photoshop CS3 through CS6 were also distributed in two different editions: Standard and Extended. In June 2013, with the introduction of Creative Cloud branding, Photoshop's licensing scheme was changed to that of software as a service and the "CS" suffixes were replaced with "CC". Historically, Photoshop was bundled with additional software such as Adobe Image Ready, Adobe Fireworks, Adobe Bridge, Adobe Device Central and Adobe Camera RAW.
Photoshop files have default file extension as .PSD, which stands for "Photoshop Document." A PSD file stores an image with support for most imaging options available in Photoshop. These include layers with masks, transparency, text, alpha channels and spot colors, clipping paths, and duotone settings. This is in contrast to many other file formats (e.g., .JPG or .GIF) that restrict content to provide streamlined, predictable functionality. A PSD file has a maximum height and width of 30,000 pixels, and a length limit of 2 Gigabytes.
CS3 improves on features from previous versions of Photoshop and introduces new tools. One of the most significant is the streamline interface which allows increased performance, speed, and efficiency. There is also improved support for Camera RAW files which allow users to process images with higher speed and conversion quality. CS3 supports over 150 RAW formats as well as JPEG, TIFF and PDF. Enhancements were made to the Black and White Conversion, Brightness and Contrast Adjustment and Vanishing Point Module tools. The Black and White adjustment option improves control over manual grayscale conversions with a dialog box similar to that of Channel Mixer. There is more control over print options and better management with Adobe Bridge. The Clone Source palette is introduced, adding more options to the clone stamp tool. Other features include the nondestructive Smart Filters, optimizing graphics for mobile devices, Fill Light and Dust Busting tools. Compositing is assisted with Photoshop's new Quick Selection and Refine Edge tools and improved image stitching technology.
CS3 Extended includes everything in CS3 and additional features. There are tools for 3D graphic file formats, video enhancement and animation, and comprehensive image measurement and analysis tools with DICOM file support. The 3D graphic formats allow 3D content to be incorporated into 2D compositions. As for video editing, CS3 supports layers and video formatting so users can edit video files per frame.