Picasa by Google
Picasa (which is totally FREE) allows you to quickly browse through the entire collection of photos on your PC. It automatically generates thumbnails of each image, which makes it easier to find what you are looking for and has incredible photo management capabilities. In addition Picasa allows you to crop, rotate and remove red-eye . It can also create on screen slide shows, print, e-mail and export your photos to the web, and order prints online (cheaper than printing your own).

FastStone
FastStone Image Viewer (FREE) 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.

Paint.NET
Paint.NET is image and photo manipulation software designed to be used on computers that run Windows XP or 2000. Paint.NET is jointly developed at Washington State University with additional help from Microsoft, and is meant to be a free replacement for the MS Paint software that comes with all Windows operating systems.

Gimp The GIMP is an opensource Image Manipulation Program. It is a freely distributed piece of software for such tasks as photo retouching, image composition and image authoring. It works on many operating systems, in many languages.

InfranView
IrfanView is a very fast, small, compact and innovative FREEWARE (for non-commercial use) graphic viewer for Windows.