non-gui tools uisng gui classes?

[tgate]

I'm trying to create a command line tool using OpenGL frame buffer  
objects and NSImage class objects.

If I import <AppKit/NSImage.h> do I also need to specify an extra  
library to link against?  I'm getting this error...

Linking tool mytest ...
./shared_obj/mytest.o:(.data.rel+0x10): undefined reference to  
`__objc_class_name_NSImage'

I'm not going to display the images, I just want to read them in work  
with them and then write them back out again.

-todd