I just tried this last night, but with Doctor Who images, at both 1/5th second, 1/10th second, and 1/20th of a second, with around a dozen pics (TARDIS, logo for revised series, characters, recurring enemies). This was usimg GIMP and its animation filter. I don't know if it was this or the fact that I watched the three-episode finale of season 3, and Utopia twice in as many days, but I had the most vivid Doctor Who themed dream since I started watching the series (and yes, I have watched marathons before without this sort of vividness).
I plan to increase the nimber of images, and play around some more with the framerate. At 1/20th of a second the entire series of pics looked like the Tardis with the logo over (image with TARDIS was diferent from image with logo), with occasional flashes of characters and, once, a Dalek. So that seems about the right framerate to test this.

(PS:I was working in ms, not fractions of a second, and this is just my calculated estimates that I made at the time based on how many milliseconds in a second. I could be wrong.)