is a pretty broad term that covers a number of areas. That having been said, here are some options:
Illustration/Drawing:AppleWorks (preinstalled on all of your eMacs)
AppleWorks provides a very nice basic drawing function. And when I say
basic that is relative to current professional apps of this type. AppleWorks is fully capable of producing professional quality work and has most of the features that people paid hundreds of dollars for in the early 90's. It is more than powerful enough for any of your needs... and you already have it.
CADintosh (nagware... free enough)
This is a little beyond illustration/drawing and into the area of drafting, but you may need to cover something like this and this is as good a tool as any.
Painting:AppleWorks (preinstalled on all of your eMacs)
AppleWorks also provides a basic painting function. This is not up to the quality of high end painting apps, but (like the drawing function) is still able to do quite a lot. It is not up to image editing... but there are other apps for those things.
Image Touch Up/Editing:ToyViewer (Free)
ToyViewer is a free image editing app that is very unassuming when you first start using it, but very powerful none the less. I strongly suggest browsing the online manual (
here) and looking at a page I wrote up on the app (
here).
PixelNhance (should be preinstalled on your eMacs, and is free)
PixelNhance is an image touch up application that provides many of the most used features in Photoshop for color/quality correction... only with a much better interface. This makes it an ideal tool for learning how these functions work, and I often times will fire up PixelNhance rather than Photoshop because the interface is just that much better.
GraphicConverter (nagware... free enough)
This is a higher end (which is why it is not free) image editing app which does have a few more advanced features over some of the others.
Animation:GIFfun (Free)
a nice GIF animation app that can help you create simple animations with your students. It's abilities cover enough to teach some of the basic concepts.
Color Theory:Apple's Color Panel (Free)
The very unassuming color panel used in most Cocoa applications is actually a very advanced tool for navigating color spaces. There is a great write up
here, and I highly suggest experimenting with the tool yourself.
I hope that at least gives you a starting point.
