Context ThumbView - description from Softdepia.com:
Context ThumbView is a Windows Explorer context menu extension that provides image preview directly in the right-click menu. It supports most of popular image file formats, including BMP, GIF, JPEG, PNG, TIFF and is very handy for quick image viewing.
Context ThumbView is invoked by right-clicking on an image file. It allows to save thumbnails, send them by email or copy to the Clipboard.
Thumbnail dimensions and additional displaying options can be configured using its Configuration Manager.
Context ThumbView is a "Free to try" program. You can download and try it for an evaluation period.