HTTPREF
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MIME Type

image/vnd.microsoft.icon

Image

Official MIME type for ICO icon files used by browsers and Windows environments.

MIME type reference, HTTP example, browser usage, common mistakes, and related content.

What is the image/vnd.microsoft.icon MIME type?

The MIME type image/vnd.microsoft.icon is used to tell browsers, APIs, and servers how a file or response body should be interpreted.

MIME stands for Multipurpose Internet Mail Extensions, and MIME types are now a standard part of HTTP responses and web content delivery.

When a browser or client receives a response with image/vnd.microsoft.icon, it uses that information to decide how the content should be processed, rendered, downloaded, or executed.

Example

Content-Type: image/vnd.microsoft.icon

HTTP example

HTTP/1.1 200 OK
Content-Type: image/vnd.microsoft.icon
Content-Length: 1256

Common file extensions

.ico

Common use cases

  • Favicons
  • Icon files
  • Windows and browser icon compatibility

Common mistakes

  • Using the wrong MIME type for the file being served
  • Returning text/plain instead of image/vnd.microsoft.icon
  • Forgetting required parameters like charset when relevant
  • Using a deprecated MIME type in older server configurations
  • Serving assets with a mismatched Content-Type header, causing browser parsing issues

How browsers use it

Browsers use the Content-Type response header to decide how a response should be handled. For example, HTML is rendered as a page, CSS is parsed as styles, JavaScript is executed as script, and images are displayed visually. If the MIME type is incorrect, the browser may refuse to load the file correctly or may treat it as plain text or a download instead.

Browser support

Supported by modern browsers, though image/x-icon remains more commonly seen in real-world setups.

Developer note

This is the more formally correct ICO MIME type, though image/x-icon is still very common.

Related MIME types