Free webp to jpg
Image MIME Reference
JPEG-LS

JPEG-LS

image/jls
VS

JPEG 2000 Compound Image File Format

image/jpm
JPM

A complete technical comparison of JPEG-LS and JPEG 2000 Compound Image File Format — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.

Equal browser support

Feature Support

Feature JPEG-LS JPM
Transparency (Alpha) ✕ No Yes
Animation Support ✕ No ✕ No
Progressive Loading ✕ No Yes
HDR Support Yes ✕ No
EXIF Metadata ✕ No Yes
ICC Color Profile ✕ No Yes
JPEG-LS
image/jls
Extension
.jls.jl
Container JPEG Bitstream
Compression Lossless / Near-Lossless (Predictive Coding)
Algorithm
LOCO-I (Low Complexity Lossless Compression for Images)Golomb-Rice Coding
Color Depth 8-bit, 12-bit, 16-bit (Per Channel)
Developed by Joint Photographic Experts Group (ISO/ITU-T) & HP Labs
Released 1999
Magic Bytes
FF D8 FF F7
Full JPEG-LS reference →
JPEG 2000 Compound Image File Format
image/jpm
Extension
.jpm.jpgm
Container ISOBMFF / JPM (ISO/IEC 15444-6)
Compression Lossy / Lossless / Mixed Raster Content (MRC)
Algorithm
JPEG 2000JBIG2JPEGMMR
Color Depth 1-bit (Text/Masks), 8-bit, 16-bit, 24-bit
Developed by Joint Photographic Experts Group (JPEG)
Released 2003
Magic Bytes
00 00 00 0C 6A 50 20 20 0D 0A 87 0A ... 66 74 79 70 6A 70 6D 20
Full JPM reference →

Browser Support Comparison

Browser JPEG-LS JPM
Chrome Chrome
Firefox Firefox
Safari Safari
Edge Edge
IE IE (Legacy)
JPEG-LS

JPEG-LS Strengths

  • Provides state-of-the-art lossless compression ratios for continuous-tone images, often outperforming Lossless JPEG and JPEG 2000
  • Extremely fast and computationally inexpensive to encode/decode, requiring no complex floating-point math or DCTs
  • Highly resilient in constrained hardware environments, making it ideal for medical equipment and deep-space probes (e.g., Mars rovers)
Limitations
  • Zero native support in web browsers or standard consumer operating systems
  • Lacks the advanced resolution scalability and progressive decoding features found in JPEG 2000
  • Primarily relegated to niche enterprise sectors (healthcare/DICOM and aerospace) rather than consumer adoption
JPM

JPM Strengths

  • Highly optimized for scanned documents, drastically reducing file sizes without sacrificing the readability of text or the quality of embedded photos
  • Supports multi-page documents within a single file
  • Object-based architecture allows for complex layout representation and independent extraction of elements
Limitations
  • Failed to achieve widespread adoption, largely being overshadowed by PDF/A and DjVu
  • Zero native web browser compatibility
  • Requires complex, specialized software to properly encode and decode the multi-layered MRC structure

When to choose which format

JPEG-LS
Use JPEG-LS when…
  • Medical Imaging (DICOM Encapsulation)
  • Space and Planetary Imaging (NASA/ESA)
  • Industrial Machine Vision
  • Scientific Archival Storage
JPM
Use JPM when…
  • Scanned Document Archiving
  • Mixed Raster Content (MRC) Imaging
  • Digital Libraries
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