What is MIME type "image/heif-sequence"?

A MIME type is a string that tells browsers and other tools how to handle a particular kind of file.

image/heif-sequence is a MIME type that designates files storing a sequence of images encoded in the High Efficiency Image File Format (HEIF).
It enables multiple frames—such as those from burst shots or live photos—to be contained in one file while keeping file sizes small and quality high.

Main use case: Storing animated or sequential images in a single container.
Efficiency: Uses advanced compression methods to save space without major quality loss.
Supports applications in digital photography and modern mobile devices.

Files using this format are commonly seen as HEIC or HEIF types.
For more technical details, check the information on Wikipedia.

Associated file extensions

.heic, .heif

Usage Examples

HTTP Header

When serving content with this MIME type, set the Content-Type header:


    Content-Type: image/heif-sequence

HTML

In HTML, you can specify the MIME type in various elements:


    <a href="file.dat" type="image/heif-sequence">Download file</a>

Server-side (Node.js)

Setting the Content-Type header in Node.js:


    const http = require('http');
    
    http.createServer((req, res) => {
      res.setHeader('Content-Type', 'image/heif-sequence');
      res.end('Content here');
    }).listen(3000);

Associated file extensions

.heic, .heif

FAQ

What is a MIME type?

A MIME (Multipurpose Internet Mail Extensions) type is a standard that indicates the nature and format of a document, file, or assortment of bytes. MIME types are defined and standardized in IETF's RFC 6838.

MIME types are important because they help browsers and servers understand how to process a file. When a browser receives a file from a server, it uses the MIME type to determine how to display or handle the content, whether it's an image to display, a PDF to open in a viewer, or a video to play.

MIME types consist of a type and a subtype, separated by a slash (e.g., text/html, image/jpeg, application/pdf). Some MIME types also include optional parameters.

How do I find the MIME type for a file?

You can check the file extension or use a file identification tool such as file --mime-type on the command line. Many programming languages also provide libraries to detect MIME types.

Why are multiple MIME types listed for one extension?

Different applications and historical conventions may use alternative MIME identifiers for the same kind of file. Showing them all helps ensure compatibility across systems.