This film roll is interesting in that it doesn't point you to the location of resources; rather, it points you to an item you can use to gain some valuable stuff. Located in the Safety Deposit Room, grab the film roll by keying in the proper code to unlock the locker its sealed in. Though, you're by no means required to develop the film roll to get the items its photograph hints towards, but it does help direct you towards what you need to do
There are plenty of convenient places to store your luggage in Denver, from downtown to Lincoln street to Capitol Hill and Commons park. The cost is just US$6 per day, and check in time is just 3 minutes. So basically, in the same time it took to make that instant cup of Ramen before rushing to the airport, you can be in and out the door with no luggage to weigh you down.