What is MIME type "image/png+json"?

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

image/png+json is a hybrid MIME type. It embeds a standard PNG image with extra JSON data. This extra data holds metadata that can include animation details, layer information, or drawing instructions.

Developers use the +json suffix to signal that besides image data, the file carries structured, human-readable information. This approach lets applications work with both binary image content and flexible metadata.

Main use case: Combines visual content with descriptive data for enhanced editing or animation.
Supports tools like Piskel canvas for pixel art creation.
Maintains compatibility for standard image viewers while offering extra features for specialized software.

For further technical details on MIME types and their structure, consider exploring more on MIME types.

Associated file extensions

.piskel

Usage Examples

HTTP Header

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


    Content-Type: image/png+json

HTML

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


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

Associated file extensions

.piskel

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.