Bounce:

How to use it:  This script takes a graphic that you specify and causes it to "bounce" around the screen. If you’ve seen my Duck Hunt game, the movement of the bird was done with this script. When the Bounce button is pressed, you will be prompted to choose a graphic to make "bounce".

To change the speed at which the image "bounces" look for a series of four lines starting with the word "var" near the very top of the script:

var x=5;
var y=2;
var offsetx=5;
var offsety=5;

By changing the value of those lines you can alter the speed of the bounce. By setting both "x" values to 0, or both "y" values to 0, you can even cause the image to bounce back and forth in a straight line, vertically or horizontally respectively.

One last thing to keep in mind, the speed at which the image bounces is dependent upon the speed of the computer it is being viewed on. If you have a slow machine and you set an image to move quickly it will likely be only a blur on a fast machine. Trust me on this one - I found this out the hard way.