Hey Machaca,
The oxy cylinder we think we are seeing is lying flat horizontally actually on top of the "frame" section you guys are discussing. Go to the absolute lower left corner of the torn skin opening and you can just barely make it out (under Peter's added word "frame".) In the bottom aft corner you can see what appears to some of us as the bottom of the composite bottle (far different from the appearance of the bottom an older style metal bottle.)
See it?
Main Oxygen cylinders on 747-100's and 200's were white, when I flew it. A walk around bottle would be green and is not a part of this conversation.