When I use the multiple playlist configuration with the dropdown playlist selection box, I would like a picture to change on the page. i.e.: if playlist1 is selected picture1 will be displayed, if playlist2 is selected, picture 1 will be replaced by picture 2 and so on.

If you use a simple HTML-DROPDOWN you can write (with prototype and bevaviour):
'#myplaylist' : function(el) {el.onchange = function() {
$('pict').src=el.getAttribute('rel'); // in rels are the location of picture
changeplaylist(el.value); // in values are the urls of XML
}
}
<select id='myplaylist'>
<option rel='/imgmypict.jpg' value='1.xml'>My finest List</option>
<option rel='/imgmyotherpict.jpg' value='2.xml'>My other finest List</option>
</select>