JPEG-HDR is an extension of JPEG, which supports images with high dynamic range. It was developed by a group that includes Radiance developer Greg Ward (see Radiance HDR), and is now apparently owned by Dolby Laboratories.
It is backward-compatible with standard JPEG viewers. The HDR data is stored in APP11 segments, and can be used to convert the image to one with high dynamic range.
See also JPEG XT, the presumed successor format.
- Some of the files at Wikimedia Commons: Category:Examples of Tone-mapped HDR imaging