pnm—The man page for pnm, the portable anymap file format, lists 31
conversion utilities related to it. However, there is no format associated
with pnm because it operates in concert with ppm, pgm, and pbm.
pbm—An examination of the man page for pbm, the portable bitmap file
format, reveals no conversion utilities. It’s a monochrome format and
serves as the foundation of the other related formats.The easiest way to resize or rotate image files is to install the nautilus-image-
converter package from the repositories. This enables you to right-click an
image when you are viewing files in the File Browser (for example, from
Places, Pictures) and choose menu options to resize or rotate one or multiple
images without opening another program.
Capturing Screen Images
You can use graphics-manipulation tools to capture images that are displayed
on your computer screen. Although this technique was used for the
production of this book, it has broader uses; there is truth to the cliché that a
picture is worth a thousand words. Sometimes it is easier to show an example
than it is to describe it.
You can use a captured screen image (also called a screen grab or a
screenshot) to illustrate an error in the display of an application (a font
problem, for example) or an error dialog that is too complex to copy down by
hand. You might just want to share an image of your beautifully crafted
custom desktop configuration with your friends or illustrate your written
documents.
When using the default desktop, you can take advantage of the built-in
screenshot mechanism (gnome-screenshot). You can use this tool by
pressing the Print Screen key. (Alt+Print Screen takes a screenshot of only the
window that has focus on a desktop.) Captured images are saved in PNG
format.
Other Graphics Manipulation Options
If you have very specific requirements for working with graphics, you may
find one of the following options better suits your needs than the general
options and comments above. Some, but not all, of these are in the Ubuntu
repositories:
Blender—A 3-D image and animation editor that you can find at