[Zope] _.getitem('some.ext') shorthand?

Given this working DTML <dtml-with "graphic"> <dtml-var "_.getitem('pythonpowered.gif')"> </dtml-with> - what would be a "shorter", more maintenance-friendly version? I would favour <dtml-var "graphic.pythonpowered"> but the problem is that I definitely must serve the file with a dotted file extension - there is no way around this. Any ideas? Is there perhaps an alternative way around the problem? I don't really care how to achieve the goal in a maintainable, robust manner, but in the end the browser needs to see <IMG SRC="http://somewhere/graphic/pythonpowered.gif"> Thanks! Stefan