How do I make a picture on a website change to another picture and then back again?

I want to load a product picture and then have it change a few times to other products. Kinda like an animated .gif but with my pictures.How do I make a picture on a website change to another picture and then back again?You write code - javascript or flash would do it - to change the pictures.
How do I make a picture on a website change to another picture and then back again?
http://fotoflexer.com/



You can do it there online for free. It's awesome. Or here:



http://www.online-image-editor.com/

pc or mac

vb