Free webp to jpg
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Image MIME Reference
PNG

Portable Network Graphics (Legacy MIME)

image/x-png
VS

AutoCAD Slide

image/vnd.sld
SLD

A complete technical comparison of Portable Network Graphics (Legacy MIME) and AutoCAD Slide — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.

PNG wins on browser support

Feature Support

Feature PNG SLD
Transparency (Alpha) Yes ✕ No
Animation Support ✕ No ✕ No
Progressive Loading Yes ✕ No
HDR Support Yes ✕ No
EXIF Metadata Yes ✕ No
ICC Color Profile Yes ✕ No
Portable Network Graphics (Legacy MIME)
image/x-png
Extension
.png
Container PNG Chunk Structure (IHDR, IDAT, IEND)
Compression Deflate (Lossless)
Algorithm
Deflate (LZ77)
Color Depth 1-bit to 16-bit (Grayscale), 8-bit (Indexed Palette), 24-bit (True Color), 32-bit (True Color with Alpha), 48-bit (High Color), 64-bit (High Color with Alpha)
Developed by PNG Development Group
Released 1996
Magic Bytes
89 50 4E 47 0D 0A 1A 0A
Full PNG reference →
AutoCAD Slide
image/vnd.sld
Extension
.sld
Container AutoCAD Slide Container
Compression Uncompressed (Vector Instructions)
Algorithm
None
Color Depth 8-bit (AutoCAD Indexed Color)
Developed by Autodesk, Inc.
Released 1980s
Magic Bytes
41 75 74 6F 43 41 44 20 53 6C 69 64 65 0D 0A 1A 00
Full SLD reference →

Browser Support Comparison

Browser PNG SLD
Chrome Chrome
✓ 1
 ✕
Firefox Firefox
✓ 1
 ✕
Safari Safari
✓ 1
 ✕
Edge Edge
✓ 12
 ✕
IE IE (Legacy)
✓
 ✕
PNG

PNG Strengths

  • The underlying format provides flawless, lossless compression and perfect 8-bit alpha channel transparency
  • Universally supported by every modern operating system, image editor, and web browser
Limitations
  • The 'image/x-png' string is an obsolete vendor quirk that forces backend developers to write redundant normalization logic in file upload scripts
  • If left unnormalized, strict MIME validators or content security policies on modern systems may incorrectly reject valid PNG files
SLD

SLD Strengths

  • Allowed for instantaneous loading of highly complex architectural and engineering blueprints on low-memory MS-DOS systems
  • Easy-to-parse binary structure containing simple opcodes for drawing vectors and polygons
Limitations
  • Completely obsolete and heavily fragmented, largely replaced by PDF and lightweight web-based DXF viewers
  • Destructive 'snapshot' format irrevocably strips all useful, editable CAD geometry data from the original drawing
  • Zero support in web browsers or standard image processing libraries

When to choose which format

PNG
Use PNG when…
  • Legacy Internet Explorer File Uploads
  • Older ASP/PHP Web Applications
  • Lossless Web Graphics
SLD
Use SLD when…
  • Legacy AutoCAD Slideshows
  • AutoCAD Custom Icon Menus
  • Historical CAD Archival

More comparisons

PNG vs ACES → SLD vs ACES → PNG vs APNG → SLD vs APNG → PNG vs AVCI → SLD vs AVCI → PNG vs AVCS → SLD vs AVCS → PNG vs AVIF → SLD vs AVIF → All comparisons →
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