JFIF Format — Complete Guide & Converter

JFIF (JPEG File Interchange Format) is the file format that most JPEG images use. The JPEG standard itself defines how image data is compressed, but not how to store it in a file in an interoperable way; JFIF fills that gap with a small header (the APP0 segment) that records a version number, pixel density or aspect ratio, and an optional thumbnail. In other words, a .jfif file is a JPEG image. Opening one reveals the same kind of DCT-compressed photo found in any .jpg file, and most .jpg files are internally JFIF (or its close cousin, Exif, used by cameras). The .jfif extension itself is what causes confusion. Windows associates the image/jpeg MIME type with the .jfif extension on some systems, so Chrome and Edge save downloaded JPEG images as .jfif files, which many websites, phone apps and editors then refuse to accept.

In practice, JFIF files are ordinary photos and web images that happen to have the .jfif extension, usually because they were saved from a browser on Windows. People then need to upload them to social networks, job and visa portals, marketplaces or school systems; add them to phone galleries; or open them in editors, which is where the extension causes problems. Because the content is JPEG, the fix is simple: convert JFIF to JPG to get a standard .jpg file with no visible change, or convert to PNG for lossless editing or to PDF for document submissions. Renaming the file from .jfif to .jpg also works in most cases. To stop new downloads from saving as .jfif, change the Extension value for image/jpeg in the Windows registry (HKEY_CLASSES_ROOT\MIME\Database\Content Type\image/jpeg) from .jfif to .jpg.