JPEG is an image format defined by the Joint Photographic Experts Group, which defined the original format and its wavelet-based JPEG2000 variant.
I will spare you the details of how the original JPEG format uses Discrete Cosine Transforms (I once wrote a baseline decoder for it), and simply point you toward a few interesting resources out there:
| Date | Link | Notes |
|---|---|---|
| Jul 18 | judge | A tool to compare visually identical images and select the best quality one |
| Older | JPEG | The JPEG Group |
| JPEG/JPEG2000 Overview | An excellent overview in PDF format | |
| JasPer | a Part-1/ISO/IEC 15444-1 compliant JPEG 2000 implementation | |
| JJ2000 | for Java |