How do you remove the headlight housing to replace the headlight bulbs?

Do you have to take the bumper off or can you reach all the bolts for the headlight assembly to remove just the headlight housing?

 

Never changed my bulbs, but dang - aren't there kind of obvious access covers on the back of the headlight units? My Volvo headlights came out by pulling a single "pin" but the Audi lights are pretty obviously designed to swap the bulbs with the headlights in place (at least mine are).