Hal,
Also, am I correct in assuming that arbitrary precision works for formula file fractals? <---<<
No, that is incorrect. It has been talked about, but has yet to be implemented. You can play with the mandelbrot fractal type with mathtolerance=-1/-1 to see the effect of the number of digits of (arbitrary) precision. Try comparing the images generated with bfdigits=4 and bfdigits=8. ...
Is the above procedure to compare two images in files correct? <---<<
Yes.
It appears that the color map of the images is used to display the difference pixels. If there are extremely dim color map values in the image one could be fooled into thinking that there were no differences between two images when in fact there were if the difference pixels that were displayed happened to use dim color map values.
A file named CMPERR is generated that lists all the differences and the color values from both images. ...
Is it likely that I did this comparison and analysis incorrectly, or is this difference between integer and float expected? <---<<
Yes, I would expect to see these differences due to the different precision between the integer math and the floating point math. Jonathan