This is really not a tutorial. It is more like a cut & paste script
This Css (Cascading Style Sheets) is used to fade images. So lets say you have
a gallery with many images, when you click the thumbnail and you are taken to
the larger version of that image and when you return to the thumbnail gallery
that thumbnail images opacity will be less dark. (Faded)
(Only Works in Internet Explorer)
To begin highlight the following code and paste it between the of your html document.
Then paste onMouseUp="className='marked'" in your image tag.
Here is an example of a full html document with the code
Hope it helps. Enjoy!