"On-The-Fly Image Editing. IrfanView is one of my main image editors that I reach for, even though I have Photoshop. It loads in an instant, and has a very rich set of tools, including mutlipage TIF support, support for multiple animated GIFs, and you can choose to use a bunch of useful plug-ins. The application isn't open source. It's freeware, but the developers improve it every year and the plug-in community works like an open source community. It's very fast to launch, does great batch image processing, and you may get things done much faster in it than in more bloated graphics applications.
"A Free Book on GIMP? In our post "6 Ways to Get Much More Out of GIMP" we collected a number of excellent resources for the powerful, free, open source GIMP graphics application, available for Windows, the Mac and Linux. You'll find a complete, free online book on GIMP, tips on getting plug-ins and more."
