Rotating/radomizing images on group home page.

Dear group, my favourite cat group has some 65 member added photos in the Group Gallery.
But only one "primary picture".

It would be nice if a mechanism was availible (to the Group Administrator) to, say, rotate each Gallery pic. as THE primary picture for a fixed period (min. daily?) or even randomly.

The random mechanism already seems to be there (random books from XYZ's library) and Tim & co. are looking at Covers (and I'm guessing this implies pictures) code.

Your thoughts.

Guido.