ShellExtension is a real handy freebie for Windows users.
Install this Tool and it will add three new options to your menu when you right click on a picture file: convert, print, and thumbnail preview.
Converting supports most of the formats you will ever need: JPEG, TIFF, PSD, PNG, GIF, BMP, TGA, PCx, and a few others. The thumbnail option is particularly handy when you are in a file open dialog of the program that lacks the image preview functionality. Clicking on the thumbnail will open the image in the default program. For printing, there are no options, you get a centered image with the file path at the top of the page.