xviewer is described as 'Linux Mint's default image viewer' and is an app in the Photos & Graphics category. There are more than 50 alternatives to xviewer for a variety of platforms, including Windows, Linux, Mac, Xfce and PortableApps.com. The best alternative is IrfanView. It's not free, so if you're looking for a free alternative, you could try nomacs or ImageGlass. Other great apps like xviewer are XnView MP (Free Personal), FastStone Image Viewer (Free Personal), XnView (Free Personal) and JPEGView (Free, Open Source).
nomacs is a small, fast image viewer able to handle the most common image formats including RAW images. Additionally it is possible to synchronize multiple viewers. A synchronization of viewers running on the same computer or via LAN is possible.
ImageGlass is a simple picture viewer with which you will be able to display your image collection in a very similar way to the one that Windows provides by default, but with some additional functions.
FastStone Image Viewer is a fast, stable, user-friendly image browser, converter and editor. It has a nice array of features that include image viewing, management, comparison, red-eye removal, emailing, resizing, cropping and color adjustments.
Background : One of the few features I missed from Mac OS X is Quick Look. It allows user peek into a file content in a lightening speed by just pressing the Space key. Windows, on the other hand, does not has this handy feature ... until now.