[Zope] Image Property?

Hi! I have a ZClass and want to add a property that references an image object. I tried to add a string property that contains the ID of the image but I couldn't come up with a way to reference the image in my view method. All the images are in the folder /images/ The image IDs have to contain suffixes (.jpg, .gif, etc). I'm pretty sure this can be done but just can't find a way how to. Can anyone help? Markus