What is a JFIF file? Why images save as .jfif and how to get JPG

JFIF stands for JPEG File Interchange Format — the standard way JPEG images have been stored since the early 1990s. Almost every .jpg file on your computer is technically a JFIF file. The data is the same; only the extension at the end of the name is different.

That's why the fix is so simple, and also why the problem is so annoying: upload forms usually check only the extension, see ".jfif", and reject a file they would have happily accepted as ".jpg".

When you save an image, the browser asks Windows which extension belongs to the "image/jpeg" type. On many PCs a registry setting answers ".jfif" instead of ".jpg" — often after another program changed it — so Chrome and Edge follow that answer.

If you're comfortable editing the registry, you can change it back: open regedit, go to HKEY_CLASSES_ROOT\MIME\Database\Content Type\image/jpeg and set the value named Extension to .jpg. Back up the registry first; if you'd rather not touch it, the options below work just as well.

For a single file, renaming is enough and loses nothing: turn on "File name extensions" in File Explorer's View menu, rename photo.jfif to photo.jpg, and confirm the warning. The image doesn't change at all.

For many files, or when renaming isn't possible (on a phone, or when you want a clean file for an upload), use Localvert's JFIF to JPG converter. It re-saves the images as standard .jpg files inside your browser — nothing is uploaded — and lets you download them all at once. Need a transparent-capable or lossless copy for editing? JFIF to PNG does that.

Besides the registry fix, you can simply type the name with .jpg at the end in the save dialog — the browser keeps the extension you type. Some image-saving browser extensions also let you choose the format. And if a site still rejects your photo after renaming, the problem is probably size or dimensions rather than the format; compress or resize it before uploading.