Free webp to jpg
Image MIME Reference
APNG

Animated Portable Network Graphics

image/vnd.mozilla.apng
VS

JPEG-LS

image/jls
JPEG-LS

A complete technical comparison of Animated Portable Network Graphics and JPEG-LS — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.

APNG wins on browser support

Feature Support

Feature APNG JPEG-LS
Transparency (Alpha) Yes ✕ No
Animation Support Yes ✕ No
Progressive Loading Yes ✕ No
HDR Support ✕ No Yes
EXIF Metadata Yes ✕ No
ICC Color Profile Yes ✕ No
Animated Portable Network Graphics
image/vnd.mozilla.apng
Extension
.apng.png
Container PNG Chunk Stream
Compression Deflate (Lossless)
Algorithm
Deflate (zlib)
Color Depth 8-bit (Indexed), 24-bit (TrueColor), 32-bit (RGBA)
Developed by Mozilla Corporation (Stuart Parmenter & Vladimir Vukićević)
Released 2004
Magic Bytes
89 50 4E 47 0D 0A 1A 0A
Full APNG reference →
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 →

Browser Support Comparison

Browser APNG JPEG-LS
Chrome Chrome
✓ 59
Firefox Firefox
✓ 3
Safari Safari
✓ 8
Edge Edge
✓ 79
IE IE (Legacy)
APNG

APNG Strengths

  • Supports 8-bit alpha transparency, completely solving the ugly 'white halo' problem inherent to GIFs
  • Gracefully degrades; viewers that do not support APNG will render a perfectly valid, static PNG of the first frame
  • Provides lossless compression that retains absolute pixel-perfect quality for UI elements and line art
Limitations
  • Because it relies on lossless Deflate compression, file sizes for complex, video-like animations can be massive compared to lossy formats like WebP or AVIF
  • Was initially rejected by the official PNG group, delaying its adoption for nearly a decade
  • Lacks native hardware decoding acceleration, unlike video-based animated formats (like MP4 or WebM)
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

When to choose which format

APNG
Use APNG when…
  • High-Quality Web Animations
  • Stickers (Apple iMessage, LINE, Discord)
  • UI Loaders with Alpha Transparency
  • GIF Replacement
JPEG-LS
Use JPEG-LS when…
  • Medical Imaging (DICOM Encapsulation)
  • Space and Planetary Imaging (NASA/ESA)
  • Industrial Machine Vision
  • Scientific Archival Storage
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