Correct MIME Type for favicon.ico?
browser, favicon, html, mime-types
Solution
When you're serving an .ico file to be used as a favicon, it doesn't matter. All major browsers recognize both mime types correctly. So you could put:
<!-- IE -->
<link rel="shortcut icon" type="image/x-icon" href="favicon.ico" />
<!-- other browsers -->
<link rel="icon" type="image/x-icon" href="favicon.ico" />
or the same with `image/vnd.microsoft.icon`, and it will work with all browsers.
Note: There is no IANA specification for the MIME-type `image/x-icon`, so it does appear that it is a little more unofficial than `image/vnd.microsoft.icon`.
The only case in which there is a difference is if you were trying to use an .ico file in an `<img>` tag (which is pretty unusual). Based on previous testing, some browsers would only display .ico files as images when they were served with the MIME-type `image/x-icon`. More recent tests show: Chromium, Firefox and Edge are fine with both content types, IE11 is not. If you can, just avoid using `ico` files as images, use `png`.
Problem
According to the Internet Assigned Numbers Authority (IANA), all .ico file falls under the MIME type `image/vnd.microsoft.icon`. (Source) E.g. `<link rel="icon" type="image/vnd.microsoft.icon" href="favicon.ico" />` However, savvy internet guru, Paul Irish, claims this is wrong, and that it would actually be `image/x-icon`. (Source) E.g. `<link rel="icon" type="image/x-icon" href="favicon.ico" />` I know you can get away with not including a "type" for .ico files, but if you were going to include one, which should it be? Are there actually any problems with serving it as official IANA type?