Universal RAW image format for saving digital photos in an uncompressed format; developed by Adobe Systems as a RAW image archival format and is supported by many image viewing and photo editing programs.
Read more about Adobe's DNG Specification.
Program(s) that open dng files
Mac: Apple Preview; Apple iPhoto; Apple Aperture 2 or later; Adobe Photoshop CS; Adobe Photoshop Elements for Mac; Adobe Photoshop Lightroom Windows: Adobe Photoshop CS; Adobe Photoshop Elements; Adobe Photoshop Lightroom; ACDSee Photo Manager; Windows Vista with Ardfry Imaging DNG codec
Information from FileInfo.com - The File Extensions Resource.
http://www.fileinfo.com/extension/dng
