Someone asked for this feature long ago. Maybe even before the forum.
Anyway, here is a quick and dirty link that will take you on a slide show through 3000 cactus images -all those listed here on the guide. I think this is a bandwidth chewing feature so I don't know if it is something to keep, especially if bots find it. But just for fun:
http://www.cactiguide.com/graphics/phpslideshow.php
(Note: at a 2 second delay, you can view all the pictures in a little over an hour and a half. )
By Request...
By Request...
All Cacti are succulents, but not all succulents are Cacti