Free webp to jpg
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Image MIME Reference
APNG

Animated Portable Network Graphics

image/vnd.mozilla.apng
VS

FastBid Sheet

image/vnd.fastbidsheet
FastBid

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

APNG wins on browser support

Feature Support

Feature APNG FastBid
Transparency (Alpha) Yes ✕ No
Animation Support Yes ✕ No
Progressive Loading Yes ✕ No
HDR Support ✕ No ✕ No
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 →
FastBid Sheet
image/vnd.fastbidsheet
Extension
.fbs
Container Proprietary FastBid Container
Compression Proprietary
Algorithm
Unknown
Color Depth Unknown
Developed by FastBid, Inc. (Scott Becker)
Released Late 1990s
Magic Bytes
Unknown (Proprietary)
Full FastBid reference →

Browser Support Comparison

Browser APNG FastBid
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)
FastBid

FastBid Strengths

  • Historically allowed the FastBid application to securely associate and load proprietary construction plans within its ecosystem
Limitations
  • Completely obsolete and unsupported in modern software environments
  • The official IANA registration of the .fbs extension causes widespread false positives, breaking modern parsers, text editors, and AI SDKs attempting to read FlatBuffers schemas

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
FastBid
Use FastBid when…
  • Legacy Construction Blueprints
  • FastBid Estimating Software
  • Causing .fbs MIME Type Conflicts (FlatBuffers)

More comparisons

APNG vs ACES → FastBid vs ACES → APNG vs AVCI → FastBid vs AVCI → APNG vs AVCS → FastBid vs AVCS → APNG vs AVIF → FastBid vs AVIF → All comparisons →
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