Short bio: Computer Scientist, FOSS supporter (read more)
Tux Machines (TM)-specific
No matter which Linux distro you run, chances are it came with a magnificent little image editor called GIMP (GNU Image Manipulation Program). Unlike Paint and other free-with-your-OS image editors, GIMP is a full featured graphics app with a broad range of capabilities that rival those os Adobe Photoshop.
In this, our first of several posts about this powerful Linux app, we'll give you a quick-and-dirty intro to GIMP's most basic features. Note that there are multiple ways to accomplish these basic tasks in GIMP, but these methods require the fewest steps. In later tutorials, we'll show you more advanced (and more efficient) image editing techniques.
Crop an Image
Cropping in GIMP is fairly straightforward. To start, open an image and select the rectangle selector from the toolbox. Then place the cursor in one corner of the area you'd like to crop. (It's often easiest to start in the upper left corner, like reading a book.) Now drag the rectangle toward the opposite corner of your desired area. (If you started in the upper left corner, you'll be dragging toward the lower-right.) Once you're happy with the selected area, right-click in the box and choose Image > Crop Image.