This custom widget does not apply to all themes. Check your theme's description first, to make sure it's included.
Paste the code below:
Paste the following code where you want to place the image:
<a href="image.jpg" rel="prettyPhoto" title="This is the description"><img src="image.jpg" width="60" height="60" alt="This is the title" /></a>
Add this script to the bottom of your .ascx file:
PrettyPhoto is a third-party lightbox.
You can find full documentation on its use at: http://www.no-margin-for-errors.com/projects/prettyphoto-jquery-lightbox-clone/documentation/