I just started putting a picture of me and my dog as the background to my computer desktop. When I'm at a speaking engagement with my laptop, the picture of me and Willow is always up on the screen. I was fooling with the Icons on the desktop one day and I thought it would be funny to put the "Recycle Bin" right in front of Willow's mouth. People thought it was hysterical.
They started coming up before and after the program to tell meall the funny stuff their dog does, eats, etc.
The bigger picture here is that if you include something personal about yourself in the presentation, people will gravitate toward you and will be MUCH MORE LIKELY TO LAUGH WHEN YOU SAY SOMETHING FUNNY. Rapport is almost instantaneous with the people that can relate to whatever personal detail you revealed. The people that don't really relate, usually don't react negatively. About the worst you'll get is a neutral response from them.
Here are some ideas of visuals you could use:
=> You with your kids/family
=> You doing a hobby
=> You at a very young age, maybe with a funny hairdo
=> You with your mom and dad
=> You at Halloween/prom, etc.
You can be sure that someone or many people will come up and comment on the photo even if you don't say anything about it at first.
Some people create entire funny segments based around the visual. Try this technique and you'll see how much fun simple personal details can be.