Requested feature: reorder slideshow asc,desc

I know that you can always put in a slideshow manually, but it would be very handy to be able to control whether the sides ascend, or descend, or go in a manual order. (File Gallery handles slide order magnificently.)
I use over 20 slide shows on the site I maintain…and for most of them the order the slides go in doesn’t matter. But for the ones that are chronological, watching the event happen backwards can be rather amusing.