DjVu is a computer file format designed primarily to store scanned documents, especially those containing a combination of text, line drawings, indexed color images, and photographs. It uses technologies such as image layer separation of text and background/images, progressive loading, arithmetic coding, and lossy compression for bitonal images.
The extension allows you to save audiovisual and textual information as a presentation or a slide show. Is used solely for viewing the created presentation and has no editing capabilities. It’s based on the XML format and can be opened with PowerPoint 2007 and newer versions. The file may be viewed by the users who do not own a commercial PC version of MS PowerPoint but who could still view the presentation using PowerPoint Viewer.