For those of you that are curious about how I make my slides for the articles of mine that appear on the main page, this post will tell you. I usually use GIMP to design the slide. A few times I use SweetHome3D or Inkscape. Some of the objects (like Tux) I download from OpenClipArt.org (public domain images and clipart). In GIMP, I can arrange the objects and add special effects or text. I love to use the tools in the "Render" menu. I occasionally experiment with different techniques and styles as can usually be seen in the slides that may appear amateur.