Except... after seeing how repetitious the images appeared on the final product... in perfect order, I added more than twice as many images (sorry, SC, if I need validation) and also ended up moving them around until they were random (and even flipping and stretching some -- basically putting them in... one by one), saving that image and using that image as an overlay layer instead of a new layer with pattern as the video shows. (I know... I could have used an external program to mix them up for me... but I didn't think it was legal.)
I originally had a more complex "overall" image... and realized that it needed to be simpler...