Free webp to jpg
Image MIME Reference
Compressed-XCF

Compressed GIMP XCF Image

image/x-compressed-xcf
VS

JPEG 2000 Codestream

image/j2c
J2C

A complete technical comparison of Compressed GIMP XCF Image and JPEG 2000 Codestream — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.

Equal browser support

Feature Support

Feature Compressed-XCF J2C
Transparency (Alpha) Yes Yes
Animation Support Yes ✕ No
Progressive Loading ✕ No Yes
HDR Support Yes Yes
EXIF Metadata Yes ✕ No
ICC Color Profile Yes ✕ No
Compressed GIMP XCF Image
image/x-compressed-xcf
Extension
.xcf.gz.xcf.bz2.xcfgz.xcfbz2
Container Gzip or Bzip2 Archive
Compression Gzip (Deflate) / Bzip2
Algorithm
DeflateBWT (Burrows-Wheeler)
Color Depth 8-bit (Per Channel), 16-bit (Integer/Floating Point), 32-bit (Integer/Floating Point)
Developed by The GIMP Team
Released 1995
Magic Bytes
1F 8B 08 (gzip) or 42 5A 68 (bzip2)
Full Compressed-XCF reference →
JPEG 2000 Codestream
image/j2c
Extension
.j2c.j2k.jpc
Container None (Raw Bitstream)
Compression JPEG 2000 (Discrete Wavelet Transform) / Lossless / Lossy
Algorithm
Discrete Wavelet Transform (DWT)
Color Depth 8-bit, 10-bit, 12-bit, 16-bit (Per Channel)
Developed by Joint Photographic Experts Group (JPEG)
Released 2000
Magic Bytes
FF 4F FF 51
Full J2C reference →

Browser Support Comparison

Browser Compressed-XCF J2C
Chrome Chrome
Firefox Firefox
Safari Safari
Edge Edge
IE IE (Legacy)
Compressed-XCF

Compressed-XCF Strengths

  • Drastically reduces the massive file sizes of standard XCF project files, saving significant disk space
  • Preserves 100% of the non-destructive editing data (layers, masks, paths, guides) from the GIMP workspace
  • Uses standard, universally supported compression algorithms (gzip/bzip2) meaning the archive can be rescued or extracted by standard OS tools if GIMP is unavailable
Limitations
  • Increases file load and save times due to the CPU overhead required to compress and decompress the massive pixel arrays
  • Impossible for automated tools to parse metadata or dimensions without first unarchiving the payload into memory
  • File extension combinations (.xcf.gz) can confuse basic MIME sniffers which stop reading at the .gz extension
J2C

J2C Strengths

  • Provides state-of-the-art wavelet compression for high-end professional workflows (Digital Cinema)
  • Allows for highly efficient progressive decoding (by resolution or quality layer) natively within the stream
  • Supports lossless mathematical compression and high bit-depths (up to 16-bit per channel) natively
Limitations
  • Lacks a standard container to store color space info or metadata, requiring external systems (like MXF or DICOM) to map colors correctly
  • Extremely computationally expensive to encode and decode compared to standard DCT-based JPEG
  • Zero web browser support

When to choose which format

Compressed-XCF
Use Compressed-XCF when…
  • GIMP Multi-layer Project Archival
  • Saving disk space for complex raster edits
  • Open-source graphic design workflows
J2C
Use J2C when…
  • Digital Cinema Packages (DCP)
  • Medical Imaging (DICOM Payloads)
  • Professional Broadcast and Archiving
  • Embedded Hardware Encoding
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