MIME Type

A MIME type, also called a media type, is a short label such as text/html or image/png that tells software what kind of content a file or response contains. It is written as a type and subtype separated by a slash, and it is how a browser knows whether to render something as a page, show it as an image, or offer it as a download. Servers send the MIME type in the Content-Type header, and data URIs include it too. Getting it wrong causes visible problems — a stylesheet served with the wrong type may be ignored, and a file with a misleading type may be handled unexpectedly — which is why matching the declared type to the actual content matters.