Since it was a survey instrument, it didn't take pictures per se, instead counting infrared photons, noting their position, time, and energy. (discovermagazine.com)
CO2 and other greenhouse gases absorb infrared photons; the energy gets moved around, some gets transferred to non-greenhouse gases by collisions, and so on. (realclimate.org)
To harvest the lost solar energy, we develop a solid - state device that turns infrared photons into visible ones, a phenomenon called photon upconversion. (energyfrontier.us)