Free webp to jpg
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Image MIME Reference
CMU-Raster

CMU Window Manager Raster

image/x-cmu-raster
VS

WebP Image

image/webp
WebP

A complete technical comparison of CMU Window Manager Raster and WebP Image — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.

WebP wins on browser support

Feature Support

Feature CMU-Raster WebP
Transparency (Alpha) ✕ No Yes
Animation Support ✕ No Yes
Progressive Loading ✕ No ✕ No
HDR Support ✕ No ✕ No
EXIF Metadata ✕ No Yes
ICC Color Profile ✕ No Yes
CMU Window Manager Raster
image/x-cmu-raster
Extension
.ras
Container CMU Window Manager Bitmap
Compression Uncompressed
Algorithm
None
Color Depth 1-bit (Monochrome), 8-bit (Indexed/Grayscale)
Developed by Carnegie Mellon University (CMU)
Released 1980s
Magic Bytes
F1 00 40 BB
Full CMU-Raster reference →
WebP Image
image/webp
Extension
.webp
Container RIFF
Compression Lossy / Lossless
Algorithm
VP8VP8L
Color Depth 8-bit
Developed by Google
Released 2010
Magic Bytes
52 49 46 46 XX XX XX XX 57 45 42 50
Full WebP reference →

Browser Support Comparison

Browser CMU-Raster WebP
Chrome Chrome
✕
✓ 32+
Firefox Firefox
✕
✓ 65+
Safari Safari
✕
✓ 14+
Edge Edge
✕
✓ 18+
IE IE (Legacy)
✕ ✕
CMU-Raster

CMU-Raster Strengths

  • Incredibly simple, uncompressed binary structure that was easy for early, memory-constrained UNIX workstations to parse and render
Limitations
  • Completely obsolete and unsupported outside of niche historical command-line tools like Netpbm
  • The shared '.ras' file extension causes frequent file misidentification and system conflicts
  • Lacks all modern imaging features, including metadata, compression, and alpha channel transparency
WebP

WebP Strengths

  • Superior lossy compression — 25–35% smaller than JPEG at equivalent quality
  • Supports both animation and full alpha transparency
  • Lossless mode available with smaller file sizes than PNG
Limitations
  • Slower encoding than JPEG, especially for lossless
  • Not supported in Internet Explorer or very old browsers

When to choose which format

CMU-Raster
Use CMU-Raster when…
  • Historical UNIX / Andrew Project Archival
  • Legacy Academic Computing Research
WebP
Use WebP when…
  • Websites
  • Ecommerce
  • Mobile Apps
  • CMS Images

More comparisons

CMU-Raster vs ACES → WebP vs ACES → CMU-Raster vs APNG → WebP vs APNG → CMU-Raster vs AVCI → WebP vs AVCI → CMU-Raster vs AVCS → WebP vs AVCS → CMU-Raster vs AVIF → WebP vs AVIF → All comparisons →
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