For blocktitle I want (and have really) some amount of image-sets, and want to be able select random-set for every block.

Well, with smarty-plugin random selection isn't problem, but... can figure how to remember choice and use rest images from the same set (without assigning smarty-var inside theme - preferred way). I.e - if I have
l-1, m-1, r-1
l-2, m-2, r-2
l-3, m-3, r-3
...
l-n, m-n, r-n
image-packs and define, what current_random=k I had to use
l-k, m-k, r-k (same index)
in all tds for blocktittle

I Can't see good solution. Any hints?