We know, from looking at an infrared image of a cat, that many things emit infrared light. But many things also reflect infrared light, particularly near infrared light. Near infrared radiation is not related to the temperature of the object being photographed - unless the object is very, very hot. "The Infrared" from The Electromagnetic Spectrum (National Aironautics and Space Administration, United States Government). https://web.archive.org/web/20060114051647/http://imagers.gsfc.nasa.gov/ems/infrared.html