The GIMP is the premiere graphics program for Linux today. GIMP (which stands for GNU Image Manipulation Program), is also available for Mac and Windows, and can be used for such basic graphics jobs as retouching photos, compositing multiple images into one, and creating an image from scratch.
As well, the GIMP can be used as a painting program, to convert images from one format to another, to do mass adjustments (such as resizing a folder full of images), and more. The GIMP has plugins and extensions to augment its already full complement of features, and also includes a scripting interface that allows for mundane tasks to be automated.
Whew… so what does all that mean? Basically, GIMP is the open-source equivalent to Adobe Photoshop. For many users, the GIMP will be sufficient. I’ve used many of the features listed above, and have been quite successful at accomplishing what I set out to do. In fact, for most people, the GIMP has more features than they’ll actually need.
For instance, the GIMP includes tools for painting, color alteration, sliders for adjusting brightness and hues, as well as cropping and rotating of the image. The GIMP also supports layers, which means a user may have one image on a particular “level,” then text on top of it. Why this is a good thing is that after text is entered, it is still alterable, so that if a change is desired, the user doesn’t need to start again. Similarly, if a particular alteration is made to a photo, then undone, the rest of the layered image remains the same.
Like Photoshop, the GIMP includes a wide variety of filters, which are one-trick scripts to enhance an image. Some of these are a variety of blur filters, which gently (or drastically) soften an image, a sharpen filter (which does the opposite), and a variety of colorizing filters, which can add a variety of different color tones to an image.
Also, the GIMP includes a good selection of lighting effects, so that highlights, flares, and realistic light reflection can be added to an image. Some of the filters are subtle, while others – such as the newsprint filter – drastically alter the image, making it look pixelated and grainy.
While some of the available tools are slightly gimmicky, others are professional-grade, such as the color correction tools. The slightest adjustment to hue/saturation, balance, brightness and threshold can be made via numeric or slider inputs. Also available is a collection of web tools, which makes turning an image into a clickable image map an easy process.
While the GIMP might not have some of the gee-whiz effects of the newer Photoshop versions, the GIMP doesn’t suffer for core power. One of the gripes, however, is in how user-friendly the GIMP is, compared to Photoshop. All of the tools are available via numerous floating palettes, which can be a bit confusing for the novice (or intermediate level) user. Likewise, when options are available as a dropdown menu, it can be a bit of a hunt to find them, as each palette has its own menus, and some are repeated from window to window.
There is a project, called GIMPShop, which attempts to alter the GIMP so that its menu structure is as identical as possible to Photoshop. While this is certainly better, it may not suit everyone, and a general rethinking of the user interface may be in order at some point.
Still in all, the GIMP is a great option for those looking for a free alternative to Photoshop, or those who don’t wish to run Photoshop in emulation (since there is currently no native Linux version available).