Taxonomy Image Display Functions

I want to use the Taxonomy Image module to display my uploaded taxonmy images as watermarks in the background of each node. The do this, I'd like to extract just the URL of the appropriate image, but the only function provided is display_taxonomy_image(), which returns a full image tag. Does anyone know of other functions associated with this module or arguments to the display function that would allow me to extract just the URL?

I could strip everything but the URL from the tag returned in PHP, but that seems inelegant, at the least.

Thanks for any assistance.