[ Note added 2013-05-13: I now have a scrot-based shell script that does this better IMHO than does Imagemagick. See http://martesmartes.blogspot.com/2013/05/screenshots-in-lxde-mate-etc.html ]
The Gnome screenshot tool has always fallen a bit short in the usability department. How do I change the default directory for storing screen shots? How do I make it default to "select area to grab"? I've always just lived with it, but tonight decided to do a little legwork to learn how to make it default to what I wanted, and I found something better.
I've long used ImageMagick for image editing. In some respects Mirage is easier to use, but Mirage doesn't handle as many image formats. I suppose the GIMP is more popular, but it's a usability nightmare.
Google led me to a wonderful page at the Webmaster Tips Blog.
Assuming one has ImageMagick installed, taking a screenshot of a selected area on the screen is as simple as typing
and then selecting the area of the screen to copy.
As a concrete example, suppose I want to capture some text from above in file selectArea.png:
The result is this, in a file called selectArea.png:
I like it.