Combination Of masking effect and photogallery

Recently I saw a website http://www.flashpro.nl/projects.html which make use of a simple masking effect to display images. However i want to implement it into this photogallery tutorial :
http://www.kirupa.com/developer/mx/photogallery.htm

I want to implement the masking effect you c in http://www.flashpro.nl/projects.html into the photogallery for every picture. Is it possible if yes how? Can someone teach me?

Thanks in advance

Note the masking effect is right at the left handside of the screen when you enter it. It is in a greenbox labelled “Featured project - blah blah blah”. Thanx Thanx