GIMP is the Gnu image Manipulation Program. It is a free piece of software developed as part of the Open Source movement. GIMP is designed to be an effective free replacement for advanced photo editing and manipulations such as Adobe Photoshop. With full control over layers, tons of filters and effects and many different image editing tools GIMP lets you take free control over your images.
Photoscape is a free photo editing tool that has a wide variety of features. The viewer lets you organize and view the photos stored on your computer. There is an editor which lets you use a number of different effects and filters to edit and optimize your image. There is also a batch editor which lets you work with multiple images at the same time. On top of this there are also options for printing, screen capture, image merging, RAW format converter and many more useful and handy tools. Easier to use than GiMP for most tasks.
Picnik is an amazing free online photo editor. Load your photos directly off your computer or from a variety of supported websites and edit them dynamically and easily in your browser window. Picnik has a free version and an ad-free advanced version available for a fee. Picnik offers a number of very useful features for on the fly photo editing.
Paint.net presents an intuitive and easy to use tabbed document interface which makes navigation of open images fast and simple. Paint.net also lets use layers, custom brushes and many other advanced photo editing tools.
UFRaw is an open source tool to help you open, adjust and resave a variety of RAW camera formats. UFRaw supports formats from many different cameras and is therefor useful to many different high end users.
