image/jp2

The official successor that never succeeded JPEG: wavelet compression from ISO/IEC 15444-1 with genuinely better artifacts at low bitrates, registered along with its jpx and jpm siblings in RFC 3745 back in 2004. The web shrugged — browser support never spread beyond Safari, and even Safari eventually dropped it — but the format quietly won specialist niches: digital cinema projects from JPEG 2000 codestreams, and medical imaging and archival scanning lean on its lossless mode. Files open with a fixed 12-byte signature box whose visible heart is jP followed by two spaces.

.jp2 is the base format; .jpx and .jpf mark the Part-2 extended format, a different registered type.

Defined by RFC 3745 · IANA registration. Registry facts from the IANA media-types registry via mime-db.