So my new computer came with this package of Adobe products, which I just installed. Eleven programs in total, it looks like, quite a few of which I have never heard of before.
I used to produce lots of PNG images, until I noticed how bad they looked when displayed on anything with a different resolution than the one the image was created in. I've become a great believer in PostScript for non-photographic material, like diagrams, graphs, etc. I have generally used something called "gnuplot" to create PostScript graphs - you write a text-file script, and then run the gnuplot program, it reads the script and creates the specified graph. Outputs can be PostScript, PNG, or many other things. But now I think "Illustrator" will allow creation of PostScript material in a point-and-click environment.
I also have "Photoshop", so I'm going to be busy creating fake moon landing photos :P