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MIME Type
image/x-icon
ImageCommon MIME type for favicon ICO files.
MIME type reference, HTTP example, browser usage, common mistakes, and related content.
What is the image/x-icon MIME type?
The MIME type image/x-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/x-icon, it uses that information to decide how the content should be processed, rendered, downloaded, or executed.
Example
Content-Type: image/x-icon
HTTP example
HTTP/1.1 200 OK Content-Type: image/x-icon Content-Length: 1256
Common file extensions
.ico
Common use cases
- Favicons
- Browser tab icons
- Legacy icon support
Common mistakes
- Using the wrong MIME type for the file being served
- Returning text/plain instead of image/x-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
Broad browser support, especially for favicons and browser tab icons.
Developer note
Still used heavily for favicons, even though PNG and SVG icons are also common now.