FastStone Image Viewer

For a free program, this multipurpose image tool strikes us as a good find. Although the main interface looks too cluttered with buttons at first glance, the three main windows are intuitive enough once get your bearings. FastStone Image Viewer for Windows boasts a nice default design, but you can customize it to your liking with several skins.
Clicking a thumbnail puts a larger view of the shot in the lower-left pane, and you zoom in simply by dragging the mouse around. Though its image-editing tools can't compete with those offered by a full-featured suite, there's still enough here to make a decent amount of tweaks to your shots. You can resize, crop, remove red-eye, and adjust color, brightness, and contrast. You'll also find a few simple effects and filters, including Lens, Waves, and Morphs. Other nifty features include multiple folder slide shows, batch cropping and Windows Vista support.
FastStone Image Viewer for Windows can batch-convert files into a number of popular image formats including GIF, BMP, PSD, and PNG, and the slide-show creator allows you to apply transitions, specify the interval between images, and add your own MP3s as a soundtrack. We can recommend this program to everyone but professional designers.