What can these images be used for?
Web banners, desktop backgrounds, video animations.
These images were all created using Fractal Architect and its random fractal creation tools.
Are there any limitations on image size or aspect ratio?
Nope. Your Mac’s memory, hard drive space, and your patience for long renders is the limiting factor.
Rendering times are directly proportional to the image area (width X height) in pixels.
See: video demos.