Instant ThumbView - Quick and easy image thumbnail viewer
Instant ThumbView is a tiny image viewer that displays image thumbnails in a tooltip window when mouse pointer is hovered over an image file in Windows Explorer. It supports a lot of popular image file formats, including BMP, GIF, JPEG, PNG, EMF, TIFF and is very handy for quick image viewing. To bring it up, open any folder with image files in Windows Explorer, and then hover an image file with your mouse pointer.