Free webp to jpg
EN
Image MIME Reference
ICO

Windows Icon (Legacy MIME)

image/x-icon
VS

MacPaint Image

image/x-macpaint
MacPaint

A complete technical comparison of Windows Icon (Legacy MIME) and MacPaint Image — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.

ICO wins on browser support

Feature Support

Feature ICO MacPaint
Transparency (Alpha) Yes ✕ No
Animation Support ✕ No ✕ No
Progressive Loading ✕ No ✕ No
HDR Support ✕ No ✕ No
EXIF Metadata ✕ No ✕ No
ICC Color Profile ✕ No ✕ No
Windows Icon (Legacy MIME)
image/x-icon
Extension
.ico
Container ICO Directory Structure
Compression Uncompressed (DIB/BMP) / Deflate (Embedded PNG)
Algorithm
NoneDeflate (via PNG)
Color Depth 1-bit, 4-bit, 8-bit, 24-bit (True Color), 32-bit (RGBA)
Developed by Microsoft Corporation
Released 1985
Magic Bytes
00 00 01 00
Full ICO reference →
MacPaint Image
image/x-macpaint
Extension
.mac.pntg.pnt.macp
Container Raw pixel payload with a 512-byte pattern header
Compression PackBits (Run-Length Encoding)
Algorithm
PackBits (Apple RLE)
Color Depth 1-bit (Monochrome)
Developed by Apple Computer, Inc. (Bill Atkinson)
Released 1984
Magic Bytes
None (Relies on classic Mac OS 'PNTG' OSType)
Full MacPaint reference →

Browser Support Comparison

Browser ICO MacPaint
Chrome Chrome
✓ 1
 ✕
Firefox Firefox
✓ 1
 ✕
Safari Safari
✓ 1
 ✕
Edge Edge
✓ 12
 ✕
IE IE (Legacy)
✓
 ✕
ICO

ICO Strengths

  • Universally supported by every web browser in existence for website favicons
  • Packs multiple resolutions into a single file, eliminating the need to serve different files for the taskbar vs. the desktop
  • Modern support for embedded PNGs (since Windows Vista) allows for excellent 32-bit transparency (alpha channels) and drastically reduced file sizes
Limitations
  • Internal file structure is convoluted due to decades of legacy cruft, such as the requirement for BMP data to lack a standard file header but double the height property for an archaic XOR/AND mask
  • Larger file size compared to a single optimized PNG or SVG, as it literally stores the same image multiple times at different scales
  • The MIME type landscape is highly fragmented (x-icon vs. vnd.microsoft.icon), causing occasional caching or strict-MIME validation errors on restrictive servers
MacPaint

MacPaint Strengths

  • Profoundly historically significant as the format that introduced millions to the concept of bitmap digital painting
  • Extremely simple PackBits compression makes it easy for emulator developers or archivists to write parsers from scratch in under an hour
Limitations
  • Severely limited: strictly black and white, and hard-locked to exactly 576 x 720 pixels
  • Lack of standard magic bytes makes programmatic file sniffing unreliable on modern filesystems without relying on the file extension
  • Completely obsolete and unsupported by modern web browsers or consumer image viewers

When to choose which format

ICO
Use ICO when…
  • Website Favicons (favicon.ico)
  • Windows Application Executable Icons (.exe)
  • Desktop Shortcut Icons
MacPaint
Use MacPaint when…
  • Historical Apple Macintosh Archival
  • Early 1980s Digital Art Preservation
  • Retro UI/UX Academic Research

More comparisons

ICO vs ACES → MacPaint vs ACES → ICO vs APNG → MacPaint vs APNG → ICO vs AVCI → MacPaint vs AVCI → ICO vs AVCS → MacPaint vs AVCS → ICO vs AVIF → MacPaint vs AVIF → All comparisons →
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