How do you do that again?

[Mystic Rover]

On one web site I visited I came across an image, whereupon when I moved the cursor over it, the image was substituted with another one. I really like that effect. Is it DHTML or JavaScript code that I should insert into my HTML document in order to try this? Is it very complex? I tried looking up some JavaScript tutorials but couldn't find the particular reference to 'toggling' images. tia

 

[Corey Bryant]

Check out this site:
http://www.dynamicdrive.com/dynamicindex15/index.html

There are a lot of mouse over effects there.

 

[Mystic Rover]

Gone to check them out. Thank You!