I took this photo on June 12, 1999 when the house was being built. This was an HP C40 digital camera, with an awesome 576 × 436 0.3 Megapixels. It seemed high-tech at the time. Today the insulation people showed up, as followup to an energy survey, to add insulation inside the floor under a luggage storage nook we have. It is insulated, but unheated, and they recommended adding additional air sealing to keep the cold air from spreading out through the between-floors space.
This photo is looking up from the front porch. In the lower left, you can see the upstairs radiant heating tubes under the living space, but NOT under the unheated storage area. In order to add air sealing, the workers were going to drill into the floor from above, and I needed to check whether they would risk drilling into the tubing. By looking at this old photo, I could tell where it was safe to drill.
You can also see that the floor joists are open trusses, with 2×4 plates and zigzag webs. This mean the entire floor space is open, so it is important to have an air barrier between heated and unheated space.
Unfortunately, this justifies my pack-rat instincts, to save 16 year old photos, but sometimes it is useful. I took video (analog!), film photos, and digitial photos of walls and ceilings, in case I ever needed to know what was in there and where.