I find that one of the most useful skills to have as a developer (besides knowing how to use a pole arm, of course), is being able to create basic graphics and edit images. Although this topic rarely, if ever, comes up in a development interview, I've lost track of the number of times it has been useful to know a thing or two about this subject. This is a particularly handy if you're the lone gunman sort of developer or if your company doesn't have a dedicated black-turtleneck-clad graphics group on hand.
When one considers doing graphics work, Adobe products usually come to mind. But for the basic graphics work that we developers are usually involved with, these products are typically too expensive. In lieu of keeping that cracked copy of Photoshop on your computer (of course you don't), there are some very good open source options available.
A great tool for doing image manipulation in the open source world is GNU Image Manipulation Program...or GIMP for short. GIMP has been in active development for over 10 years, has become a very mature raster editor, and has a thriving community. Although not as easy to use as Photoshop, which is a terrific, simple-to-use and powerful image editor, GIMP has all the basics for image manipulation and plenty of filtering capabilities. Furthermore, it's compatible with Photoshop PSD files out of the box and can open PostScript documents, such as EPS images, with the help of the opensource tool Ghostscript. (After install, simply copy gswin32.exe and gswin32c.exe into GIMP's bin directory.) Furthermore, GIMP has basic vector drawing capabilities (lines, circles, shapes, etc) via the GFig module which is included with GIMP upon install. (A user guide is available showing what's available in GFig.) Between GIMP and GFig, I find that 95% of my graphics related work is covered.
If you're needing to create brand new images and/or have an artist's touch, you'll want to consider Inkscape. This does not have the image editing capabilities of GIMP, but is perfect for building graphics from the ground-up with capabilities similar to Adobe Illustrator; albeit, without as many bells and whistles. The GUI is also very similar to Illustrator which will be an added benefit if you're already used to it.
With GIMP and Inkscape, your image creation and editing needs are pretty much covered without having to bug the "graphics dude" every time you need to have an image cropped.
07-25-2007 9:40 AM