random photo in sidebar (with a link) ?

i’ve been working with several galleries recently to try to decide which is better for me.
i love iPAP’s look, and SPG even more for it’s simplicity.
whichever i decide upon, both generate thumbnails and store them all in a folder.
so i thought i’d take a shot at trying to create a random image post in my sidebar.
i installed the rotator.php and called it with a simple html tag (replacing the name of the image with the “folder/rotator.php” link.
it’s great for displaying the thumbnails, but they are not linked to the actual photos posted within the gallery.
how do you do that?
examples:
this is the author of SPG’s sidebar
https://relativelyabsolute.com/archives/2004/07/spg-and-hotlinking/
This is the standard Gallery sidebar add on.
https://zed1.com/journalized/
I don’t have the skills to write something like this from scratch, although i can see the funtions and how they call up the images. I just don’t seem to be having any luck with the association between the tumb and the image, or making that information random.
puzzled.
F.