How MIME types are written
The label has two parts separated by a slash: a broad type and a specific subtype. Image files use image/jpeg, image/png, and image/webp, while documents use application/pdf.
The system began as a way for email to carry attachments of different kinds, and it now underpins how browsers, servers, and operating systems agree on what they are handling. The first word names the broad category, such as image or application, and the second pins down the exact encoding.
Common types for images and documents
Knowing the standard labels helps when a form or API asks for one. Mismatches between the extension and the true type are a common source of rejected uploads.
Some types are interchangeable in practice: .jpg and .jpeg both declare image/jpeg, and the subtype for GIF is image/gif. Servers rely on the same labels when they decide whether to show a file inline or force a download.
- image/jpeg for JPG and JPEG files
- image/png for PNG files
- image/webp for static WebP files
- application/pdf for PDF documents
- application/zip for ZIP archives
MIME types in browsers
Browsers use the type to decide whether to display a file inline or download it, and servers send it in headers so the receiving end can react correctly.
Filekind's outputs follow these conventions, producing standard JPEG, PNG, WebP, PDF, and ZIP files that other software recognizes without special handling. Because the results are ordinary files, they can be attached to email or posted to a form without extra steps.