The BetterZip Quick Look Generator extends OS X's Quick Look functionality to let you inspect the contents of compressed archives.
The BetterZip Quick Look generator has now been unified with and integrated into BetterZip. It's still completely free to use for everyone, only easier to install and update. Just download BetterZip, put it in your Applications folder and you are ready to go.
The currently supported archive formats are: ZIP, RAR, 7-Zip, TAR, TGZ, TBZ, TXZ, GZip, BZip2, ARJ, LZH, ISO, CHM, CAB, CPIO, DEB, RPM, StuffIt's SIT, BinHex, and MacBinary. And now also Apple Disk Images (DMG) and winmail.dat!
Registered users of BetterZip get two bonus features in the QL generator: You can click any file in the QL panel and command will be handed over to BetterZip which will extract and display the clicked file. And there is a drop-down list in the QL panel with all your extraction presets. Choose one and BetterZip will extract the archive using the chosen preset.
You can set the various options directly in the Quick Look pop-up. Just click the Preferences button in the upper right area. Set your options and click the button again to hide it.
If you are stuck on an older version of OS X than 10.9, please get one of the legacy versions. Install it by unpacking and copying the BetterZipQL.qlgenerator bundle to your /Library/QuickLook folder (if you want to install it for all users on your Mac) or to the ~/Library/QuickLook folder, this is the Library/QuickLook folder inside your user folder. You may need to create the QuickLook folder inside ~/Library first.
The Quick Look framework will need a little time before it realizes that a new generator has been added. If you are impatient and not afraid of using the terminal, you can execute the following command to make the Quick Look framework reset immediately:
> qlmanage -r
or you could restart the Finder. Or logout and -in again. Or restart your Mac. Or take a nap. You choose.