Convert between image formats from the Windows shell. Supports JPG, BMP, PNG, GIF, ICON, and several other file formats. Also can rotate/resize images. Right click on a file or a group of files in Windows, and select Convert
Developer: Kristanix Software
Free to try; $14.95 to buy | Windows 98/ME/NT/2000/XP
IconX turbo-charges your Windows desktop icons. It can insert shadows, make icons bigger, make icons zoom up when you mouse over them, and even change their color based on what you're doing.
Developer: Stardock Systems
Free to try; $9.95 to buy | Windows 2000/XP