[Zope] String to object ID

We have a short snippet of code that builds an image name from properties when a web page is called. We need to use this string to directly call the image object and display it in the page. For the life of me I cannot figure out how to coerce a string into an object id. Any hints? currently: <dtml-with "_.namespace(imagename='images.hd' + section)"> <dtml -var imagename> </dtml-with> this correctly prints the name of the image object we want. 'images.hd.thisimage' How do I use that to display the image? DAve.