On escape time algorithm fractals (eg Mandelbrot), FRACTINT allows for interruption in the calculation of the image. For example, if a fractal takes 3 hours to calculate, you could let the program work for 2 hours, save the partially completed version of the fractal, and exit the program. Upon restarting the program, you could restore the partially completed image, and use the included metadata to continue with the calculation from the point at which you had interrupted the calculation - you don't lose the work done over the first 2 hours. What happens with fractal flames? When the screensaver is in the process of rendering an image, is the work done up to that point completely lost if I exit the screensaver? I always feel guilty when shutting off the screensaver, thinking that the work in progress has disappeared.