Thermal Image showing moisture as purple areas  View with the naked eye 
What we see with thermography is a temperature difference at the surface of the ceiling/walls. It is vital to make sure the thermographer has been properly trained and can document that training. Also, ALL "anomolies" (areas of significant temperature differences) should be confirmed with a moisture meter. Ensure your building inspector/thermographer is qualified to identify the water leak detection issues that are affecting your family, home or business.