Image format

.ico

Icon File Format

ICO is the icon file format used by Windows for application icons and website favicons. It can contain multiple image sizes and color depths in a single file.

MIME type

image/x-icon

Developer

Microsoft

Introduced

1985

Advantages

  • Multiple sizes in one file
  • Standard for Windows icons and favicons
  • Widely supported by all browsers
  • Small file sizes

Limitations

  • Limited to small image dimensions
  • Primarily Windows-focused format
  • Being replaced by PNG favicons in modern web
  • Complex internal structure for a simple purpose

When to use ICO

Website favicons
Windows application icons
Desktop shortcuts
Taskbar and system tray icons

Technical details

ICO files contain one or more BMP or PNG images at different sizes (typically 16x16, 32x32, 48x48, 256x256). Each image can have its own color depth from 1 to 32 bits per pixel.

Convert to ICO from other formats

9 formats can be converted to ICO

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