JPG vs. JPEG image formats

Question

I often use JPEG images, and I have noticed that there are two very similar file extensions: .jpg, which my mobile\'s camera and the Preview

Answer 1

They are identical. JPG is simply a holdover from the days of DOS when file extensions were required to be 3 characters long. You can find out more information about the JPEG standard here. A question very similar to this one was asked over at SuperUser, where the accepted answer should give you some more detailed information.