To show multiple images in one block

I am using v1.5, standalone.

Say if I want to show a matix of 2x5 random images, I know I can do it by calling the random-block file 10 times from the same page. But it will overload the server for a busy page.

Anyone can tell me how to hack the file so one single call of random-block.php can load up 10 (or X) random pics out of my thousands?

Thanks,

Chow