Exclude certain categories and/or filetypes from random and newest

[AuroraMike]

As the subject says, can it be done? I have "private" (aka not general public) galleries and then I have others that are media content (mpeg, avi, swf) and I'm not too keen of the generic gif showing up in the recent and random bars. But I do like that feature, just not for all categories.

[Xil Ze]

i'd like to know if this is possible too. also, is there a way to exclude an entire crop of subcategories from showing up in new/random images based on their head category?