JPEG (pronounced jay-peg) is a commonly used method of compressing photographic images. The compression algorithm is “lossy” in that information is removed from the image to assist with decreasing the file size. The greater the compression, the more information is discarded. Files that have undergone jpeg compression usually have extensions such as .jfif, .jpeg, or jpg.
The name stands for Joint Photographic Experts Group. JPEG itself specifies only how an image is transformed into a stream of bytes, but not how those bytes are encapsulated in any particular storage medium. JPEG is the most common format used for storing and transmitting photographs on the World Wide Web. It is not as well suited for line drawings and other textual or iconic graphics because its compression method performs badly on these types of images (it is better to use the PNG and GIF formats for such purposes.
Most digital cameras also create files that are in JPEG format. A testament to the popularity of the standard.