Well, this is my first serious attempt to make an image using GIMP, the Linux Graphics Manipulation Tool.

I used one of my Starfield backgrounds that I'd done up in Photoshop, then started filtering on a new layer. The "Portal" in the middle is actually a coffee stain filter. :) Then I used a filter that edges it in (Blue cornea in this case), lighting effects and lens flares/super nova filters from HELL all over the place on the different layers.

Not quite done yet, have a few more ideas to try out on this image. I'll post the final one when I'm done messing around, if I ever bother. I likely won't.