Is there a way to print the directory that is in thumbnails mode other than Alt+PrtScr DOpus itself - to get the directory printed like an album? Having the possibility to turn the filenames off would also be handy.
I don't think there is.
However, there are some screenshot utils* that can capture the contents of a scrolling window (e.g. an Opus thumbnails lister) into one long image which you could then print. I guess you'd run into problems with thumbnails spanning the page breaks, though.
(* While I have not used either of them, Snag-It says it can and Screenshot Studio probably can as well since the related FireShot Firefox extension can do it for web pages. Maybe there are some others, too.)