How to Open a JFIF File on a Mac

The short version

macOS is the easiest platform for this. Unlike Windows and unlike the iPhone Photos app, macOS identifies files by inspecting their contents, so a .jfif file is recognised as a JPEG almost everywhere. Double-clicking usually just works.

If you landed here, something did not work — so here is each case in turn.

Double-click, and Preview opens it

Preview has handled JFIF for many years. You can also select the file in Finder and press Space for a Quick Look preview without opening anything.

When double-clicking does nothing

This means the file association is missing or was claimed by an app that then refused the file.

1. Right-click (or Control-click) the file.
2. Choose Open With → Preview.

To make it permanent for every .jfif file:

1. Select the file and press ⌘+I to open Get Info.
2. Expand Open with and choose Preview.
3. Click Change All… and confirm.

Converting one file with Preview

1. Open the file in Preview.
2. Choose File → Export…
3. Set Format to JPEG, adjust Quality if you want, and save.

Note that this decodes and re-encodes the image, which is a second lossy pass. Quality at maximum is visually harmless, but if you want the original data preserved exactly, rename the file instead or use a converter that copies the compressed stream rather than rebuilding it.

Converting a whole folder — the built-in way

This is the feature people install software for without realising macOS already has it. It needs macOS Monterey (12) or later; on older versions use the Terminal method below, which works on every Mac.

1. In Finder, select every .jfif file you want to convert.
2. Right-click the selection and choose Quick Actions → Convert Image.
3. Pick JPEG, choose an image size, and click Convert to JPEG.

Converted copies appear alongside the originals. It handles hundreds of files without complaint, and nothing is uploaded.

Converting from Terminal with sips

Every Mac ships with sips (Scriptable Image Processing System). If you are comfortable in Terminal it is the fastest option of all.

# one file
sips -s format jpeg photo.jfif --out photo.jpg

# every .jfif in the current folder
for f in *.jfif; do sips -s format jpeg "$f" --out "${f%.jfif}.jpg"; done

# check what a file really is before converting
sips -g format -g pixelWidth -g pixelHeight photo.jfif

That last command is genuinely useful: it reports the real format from the file's contents, so you can catch a PNG that someone renamed to .jfif.

Renaming in Finder

Select the file, press Return, change the ending to .jpg, press Return again, and confirm Use .jpg when macOS asks.

If you cannot see the extension, open Finder → Settings → Advanced and tick Show all filename extensions. Renaming changes nothing inside the file, so there is no quality loss at all.

Photoshop, Lightroom and Affinity

Lightroom is the common trap. Because it filters by extension during import, a folder of .jfif files looks empty. Run the Finder batch conversion above before importing.

Converting in the browser instead

If you would rather not re-encode anything, our JFIF to JPG converter copies the compressed JPEG data across untouched — the output is byte-identical to the input. It runs inside Safari or Chrome on the Mac itself, so no file is uploaded.

That is the one advantage it has over Preview and sips, both of which rebuild the image.

A note on AirDrop and Windows senders

If a colleague keeps AirDropping or emailing you .jfif files, the cause is on their machine, not yours — a Windows registry value that makes downloaded JPEGs save with that extension. Sending them the one-line fix solves it at the source and saves you both the conversion step.