Thought I'd mention that IDL is a nice language for doing image processing. It does require a fair amount of programming though it gives one a lot of flexibility. IDL licenses can be costly, however there is a new freeware version of IDL called GDL. There are a number of library procedures that come with the package, and more can be added by either writing your own or by scouring the web. I use IDL quite a bit in a Linux environment.
Here is a link to download the GDL software: http://gnudatalanguage.sourceforge.net/
This page has binaries for the Mac and source code for Linux. For Windows, one could use Cygwin to run Linux, though I have yet to get the GDL source code to fully compile in that environment.