Google's free image manager and editor that quickly and smartly modifies digital images, offering a smart interface and a sense of fun, with "warmify" and "I'm feeling lucky" being two of the image effect options. Picasa makes it easy to turn one's images into collages, posters, movies, and other goodies. For anyone who wants to quickly view, manage, and edit the 100s and 1000s of pictures one can generate with a digital camera, Picassa is the best solution.
(not free) The image editing software used by most web and desktop publishing professionals the world over. While learning Photoshop can be a daunting task, adeptness with the program allows users to enhance and/or alter digital images in a seemingly infinite number of ways.
Just put "http://aviary.com" in the front of any webpage URL ... that webpage then comes up inside an image editor, including graphics and effects editor. This is a free scaled down version of Photoshop.
A screenshot utility that was developed for software testers who use bug tracking systems. Ability to highlight, notate and/or crop areas of the screenshot. Screenshots can also be sent to Skype or a default E-Mail application.
Part of Apple's iLife software that comes installed on all new Macs or can be bought separately, iPhoto is an excellent way to manage and present your digital image collection. In addition to its elegantly simple interface and powerful options for publishing/sharing your photos, and includes robust image editing tools as well.