how do I make a picture change to another picture when clicked on?

[josephcardoza]

Here's what I am trying to do:

1. I have a picture of the state of california with a "star" where Sebastopol California is. I want to be able to click on the star on the state picture and have the picture completely change to a different picture (in this case a map of the local area).

2. Is there any way I could roll over the star on the state map and have it double in size and THEN upon clicking switch to a different picture.

I know its simple but I am drawing a blank and I really appreciate help.
case a map of the local area).