Free webp to jpg
Image MIME Reference
Compressed-XCF

Compressed GIMP XCF Image

image/x-compressed-xcf
VS

BlockFact Image

image/vnd.blockfact.facti
FACTI

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

Equal browser support

Feature Support

Feature Compressed-XCF FACTI
Transparency (Alpha) Yes Yes
Animation Support Yes ✕ No
Progressive Loading ✕ No ✕ No
HDR Support Yes Yes
EXIF Metadata Yes Yes
ICC Color Profile Yes Yes
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 →
BlockFact Image
image/vnd.blockfact.facti
Extension
.facti
Container BlockFact Authenticated Container
Compression Container (Inherits payload compression, e.g., JPEG/PNG)
Algorithm
None (Pass-through to embedded payload)
Color Depth Inherited from payload
Developed by BlockFact
Released 2025
Magic Bytes
Unknown (Proprietary Container)
Full FACTI reference →

Browser Support Comparison

Browser Compressed-XCF FACTI
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
FACTI

FACTI Strengths

  • Provides undeniable, mathematically verifiable proof of a photo's origin (time, location, and device) via the StarkNet blockchain [1.3.1]
  • Privacy-first design utilizes zero-knowledge proofs (Groth16), meaning the actual image is never uploaded to a central server or blockchain
  • Invisible watermarking ensures that even if the image is screenshotted or cropped, tampering can be detected
Limitations
  • Lacks native rendering support in web browsers and standard image viewers, requiring specialized software to view
  • Requires blockchain registration at the moment of capture, making it incompatible with existing legacy photos
  • The proprietary nature of the container limits integration to environments supporting the BlockFact SDK

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
FACTI
Use FACTI when…
  • Journalism and Media Authentication
  • Legal and Insurance Evidence
  • AI Deepfake Prevention
  • Content Provenance and Authorship
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