This photo comes directly from The Gateway to Astronaut Photography of Earth, a government website operated by NASA at the Earth Sciences and Image Analysis department at Lyndon B. Johnson Space Center. They are responsible for training the astronauts in Earth observations, cataloging and archiving the photographs that astronauts take from space using hand held cameras and more. Here is the homepage, as you can see it has a .gov URL It’s very interesting that they would allow a photo like this one to be put up on the website.
Please keep in mind that a UFO stands for “Unidentified Flying Object.” I am not claiming that this particular UFO is extraterrestrial in origin.
For those of you new to the UFO topic, here is a quick introduction done by historian and UFO researcher Richard Dolan.