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Image MIME Reference
ACES

ACES Image Container File

image/aces
VS

Apple PICT Image

image/x-pict
PICT

A complete technical comparison of ACES Image Container File and Apple PICT Image — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.

Equal browser support

Feature Support

Feature ACES PICT
Transparency (Alpha) Yes Yes
Animation Support ✕ No ✕ No
Progressive Loading ✕ No ✕ No
HDR Support Yes ✕ No
EXIF Metadata ✕ No ✕ No
ICC Color Profile ✕ No ✕ No
ACES Image Container File
image/aces
Extension
.exr
Container OpenEXR (SMPTE ST 2065-4)
Compression Lossless / Uncompressed
Algorithm
PIZZIPRLEB44Uncompressed
Color Depth 16-bit (Half-float), 32-bit (Float)
Developed by Academy of Motion Picture Arts and Sciences (AMPAS) / SMPTE
Released 2013
Magic Bytes
76 2F 31 01
Full ACES reference →
Apple PICT Image
image/x-pict
Extension
.pict.pct.pic
Container QuickDraw Metafile
Compression Uncompressed / Run-Length Encoding (RLE) / QuickTime Compressors (JPEG, SMC)
Algorithm
Apple PackBits (RLE)QuickTime Image Compression Manager (ICM)
Color Depth 1-bit, 2-bit, 4-bit, 8-bit (Indexed), 16-bit (High Color), 24-bit (True Color), 32-bit (RGBA)
Developed by Apple Computer, Inc.
Released 1984
Magic Bytes
None (Requires offset parsing, e.g., 00 11 02 FF at byte 522)
Full PICT reference →

Browser Support Comparison

Browser ACES PICT
Chrome Chrome
✕ ✕
Firefox Firefox
✕ ✕
Safari Safari
✕ ✕
Edge Edge
✕ ✕
IE IE (Legacy)
✕ ✕
ACES

ACES Strengths

  • Industry standard for high-end visual effects, compositing, and color grading
  • Supports 16-bit half-float data, accurately capturing immense dynamic range without clipping
  • Standardized by SMPTE (ST 2065-4) to guarantee universal color interoperability across different post-production facilities
Limitations
  • Considerably larger file sizes than conventional consumer image formats
  • Completely unsupported in web browsers and most standard desktop viewers
  • Requires specialized compositing or color grading software to interpret and view the scene-linear data correctly
PICT

PICT Strengths

  • Incredibly versatile for its time, allowing a single file to cleanly scale text and vector shapes while simultaneously housing raster photos
  • Served as the flawless universal clipboard format for the classic Mac OS, enabling seamless copy/pasting between wildly different applications
Limitations
  • Deeply tied to Apple's legacy QuickDraw graphics architecture, making it exceptionally difficult to write accurate third-party parsers on modern operating systems
  • Lack of a standard magic header makes file detection unreliable without seeking 522 bytes deep into the file
  • Completely unsupported in modern web environments and discontinued by Apple itself

When to choose which format

ACES
Use ACES when…
  • Visual Effects (VFX)
  • Digital Intermediate (DI)
  • Color Grading
  • Archival
PICT
Use PICT when…
  • Classic Mac OS Clipboard Data
  • Legacy Macintosh Desktop Publishing (Aldus PageMaker, QuarkXPress)
  • 1980s/1990s Digital Clip Art

More comparisons

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