JPEG (.jpe, jpg, .jpeg, .jff, jfif, .jpe, .jtf), Joint Photographic Experts Group, named after the committee that designed the standard image algorithm. It is defined in RFC 2045 and RFC 2046. JPEG is designed for compressing either full-color or grayscale digital images of "natural" real-world scenes.

For more details see the Wikipedia article: JPEG

For the digital library, convert JPG images to PDF for the image version and upload the original JPG as the archive version.