[xelawho]

although if you are changing the image onclick, you may end up with an object of objects, and you can use the name of the sub-object to retrieve the data:

<script>
var fotos={
		dog:{title:"Fido", 
		filename:"Fido.jpg", 
		item:"3706", 
		caption: "woof!", 
		avail: "available"
		},
		cat:{title:"Whiskas", 
		filename:"Whiskas.jpg", 
		item:"9384", 
		caption: "meow!", 
		avail: "sold out"
		}
	}	
var pic1="dog";
var pic2="cat"		
alert(fotos[pic1].filename);
alert(fotos[pic2].caption);			
 </script>

That's the basics (or the easiest-to-maintain that I can see) - the finer points depend on how your page is set up and what you want to do