FileHint
JAEN

.ico

Low risk

Windows Icon

The native Windows icon format. A single file can hold multiple resolutions and colour depths — still the default for desktop icons and legacy web favicons.

MIME types

  • image/x-icon
  • image/vnd.microsoft.icon

Category

image

What opens this file

  • IcoFX
  • Greenfish Icon Editor Pro
  • Photoshop + plug-in
  • ImageMagick

How to open by OS

Windows

  • Explorer and IcoFX.

Mac

  • Preview and Pixelmator.

Linux

  • GIMP, Inkscape.

Ios

  • Viewing only.

Android

  • Viewing only.

Safety notes

  • Historical ICO parser CVEs have caused DoS-level hangs when crawling malicious favicons. Keep browsers current.

Common mistakes

  • A favicon with only one resolution looks blurry on Retina displays. Bundle 16×16, 32×32, 48×48, and 64×64.
  • Modern sites increasingly supply PNG or SVG icons via <link> tags and skip .ico altogether.

Related extensions

References