Gloobus-Preview is an extension for the Gnome Desktop Environment designed to enable a full screen preview of any kind of file. It’s based on Apple’s “Quicklook”.it is based on apple Quicklook feature.
In other words, you can access a huge number of file types without first launching the applications associated with that file first. It's useful for browsing your pictures (from, say, last night pub) or to create a simple slide show on your desktop.
The ‘Preview’ Mode
The Preview mode is without a doubt, Gloobus star. It allows instant access to a variety of file types without the need of opening their default application. It allows you to take a quick look at the content of a file on the fly, saving you valuable time and CPU resources.
You can access the preview mode from several ways, right click on the file you want to preview and choose “Preview” o simply hit the Space key on your keyboard.
Video and audio files can be navigated on preview mode by dragging the slider of the progress bar at any given time.
Supported File Types
Images: jpeg / png / icns / bmp / svg / gif / psd / xcf
Documents: pdf / cbr / cbz / doc / xls / odf / ods / odp / ppt
Audio: mp3 / ogg / midi / 3gp / wav
Video: mpg /avi / ogg / 3gp / mkv / flv
Other: folders / ttf / srt / plain-text
Installation is easy for Ubuntu and ArchLinux users , just download deb packages off Gloobus official web. for other linux distros , source code is available as well.