This plugin allows you to look into ATR atari image files commonly uset with various Atari 8-bit emulators (for example open-source Atari800 running on allmost all operating systems) Simply press space, and get information about Disk size, density, files and free space.

To install, simply drop qlatrviewer plugin into /Library/QuickLook or ~/Library/QuickLook and run qlmanage -r in the Terminal, or simply logout and login again.