Browse all MIME types

image/vnd.microsoft.icon

ICO packages one or more favicon sizes in a format browsers and desktop systems still expect for app and site icons.

image
Compressible in transit

Content-Type header

Content-Type: image/vnd.microsoft.icon
Common extensions
.ico

How teams usually encounter it

This page maps the media type to the file extensions and delivery behaviors developers usually care about: browser parsing, upload validation, cache correctness, and asset handling.

Compression signal

image/vnd.microsoft.icon often benefits from gzip or Brotli in HTTP delivery because the payload is text-like or structurally repetitive.

Server config snippets

Use these when a server is missing the right extension-to-MIME mapping or you want the expected header to survive a proxy, CDN, or custom asset bucket setup.

Nginx
types {
  image/vnd.microsoft.icon ico;
}
Apache
AddType image/vnd.microsoft.icon .ico

Magic bytes / file signature

When you need to validate uploads or investigate a mislabeled file, the signature often starts with 00 00 01 00.

Operational shortcut

If a browser downloads this asset instead of rendering it correctly, check the response header first, then verify the extension mapping on your origin and edge cache. .ico is the fastest sanity check for teammates reviewing the file outside the app.

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