What is MIME type "image/x.mrsid"?

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

The MIME type image/x.mrsid identifies files encoded with the proprietary MrSID compression scheme. This scheme handles large raster images with high compression while retaining necessary detail for mapping and geospatial work.

It is engineered for efficient storage and rapid display of very large images. This capability is essential in systems that require smooth zooming and panning, like advanced mapping or remote sensing applications. Files using this type often need specialized software to decode the image streams correctly.

Primary Use: Optimized storage and fast rendering of high-resolution geospatial imagery.
Functionality: Implements multi-resolution tiling for progressive image display.
Applications: Commonly used in GIS systems, digital mapping, and remote sensing projects.
Technical Note: Although non-standard, it is widely recognized in geospatial imaging software.

Files of this format typically have the extension SID.

For further technical information, refer to the details on MrSID on Wikipedia.

Associated file extensions

.sid

Usage Examples

HTTP Header

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


    Content-Type: image/x.mrsid

HTML

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


    <a href="file.dat" type="image/x.mrsid">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/x.mrsid');
      res.end('Content here');
    }).listen(3000);

Associated file extensions

.sid

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.