Grafx2 is a bitmap paint program that allows you to draw in more than 60 video resolutions (from 320x200 to 1024x768, including most of the standard Amiga resolutions: 320x256, 320x512, 640x256, 640x512, and more, provided your video card knows how to handle them). Its layout is not very different from the famous Deluxe Paint or Brilliance, so it will be quite easy to handle it if you know at least one of these programs.
ucanvcam is a cross-platform framework for building virtual cameras. Virtual cameras offer the same interface as regular cameras to client applications (such as Skype), but provide user-generated or user-modified imagery rather than imagery directly from a camera. While ucanvcam comes with a set of special effects, the main intent is to make building virtual cameras easier for people without OS-specific knowledge, so they can focus purely on image processing.