PreviewQt is a very simple application for previewing a wide range of files. Its main aim is on speed, striving to provide a preview as instantaneously as possible. It achieves this by being very lightweight and by its ability to sit in the system tray, ready to show whatever is thrown at it.

Supported file formats include:

• More than 140 image formats
• All of the common video formats
• Photo spheres and 360 degree panoramas (that use equirectangular projections)
• Motion photos, Micro videos, and Apple live photos
• PDF documents including page navigation
• Archives (zip, tar.gz, rar, 7-zip) with the ability to explore its content
• Comic Books (cbz, cbt, cbr, cb7) including page navigation
• E-Books (epub) including navigation and font scaling
• Text files including syntax highlighting and search feature

If you are using Dolphin file manager, PreviewQt can be invoked by shortcut to load whichever file is currently highlighted to allow for previewing any file easily without having to se PreviewQt as default application. You can pass files to PreviewQt by means of a remote application (small square) wth any file dropped on it passed on to PreviewQt. If you are running KDE Plasma 6, there is also a plasmoid that integrates nicely with your desktop.

If you like the overall concept of PreviewQt but would like to have more features, check out the fully featured image viewer PhotoQt.