See .heic vs .jpg photo extensions in Finder

You drag a photo into a web form and it bounces back: "unsupported file type." The thumbnail looked like every other picture in the folder, so how were you supposed to know it was a HEIC and not a JPEG? You weren't — because Finder was hiding the one detail that mattered. Switch on Finder → Settings → Advanced → Show all filename extensions and every photo declares itself as .heic, .jpg, .png, or .dng before you ever try to upload it.

Why photo formats are invisible by default

Finder generates a thumbnail from the image itself, so a HEIC and a JPEG of the same shot look pixel-for-pixel identical in the grid. The format only surfaces when something downstream cares — and plenty of things do. iPhones shoot in HEIC by default to save space, but many websites, older Windows PCs, some email clients, and a lot of design tools still expect JPEG or PNG. Hand them a .heic and you get a rejected upload, a broken preview, or a file that simply won't open on the other end.

The reverse bites too. You export "web-ready JPEGs," but a couple of originals slipped through as HEIC, and now half your gallery is broken for visitors. When every file shows the same thumbnail and no suffix, you can't audit a folder by looking at it. Turning extensions on makes the format part of the name, so mismatches are obvious at a glance.

Turn on extensions for your photos

1. Open a Finder window and press Command+Comma to reach Finder → Settings.
2. Click the Advanced tab.
3. Turn on Show all filename extensions.

Every folder — including where AirDrop and Photos exports land — now shows the true suffix, on macOS 13 Ventura, 14 Sonoma, and 15 Sequoia. Prefer a command? This flips the same setting and shows how to undo it:

# Show extensions on every file, then relaunch Finder
defaults write NSGlobalDomain AppleShowAllExtensions -bool true
killall Finder

# Undo — hide extensions again
defaults write NSGlobalDomain AppleShowAllExtensions -bool false
killall Finder

Sort a folder before you upload

With suffixes visible, prepping a batch of photos for a website or a client becomes quick:

• Switch to list view (Command+2) and click the Kind column header — all your HEIC files gather in one block, all your JPEGs in another, so you can see the split instantly.
• Spot the outliers — a single .heic in a folder of .jpg exports jumps out, and a stray .dng raw file won't sneak into a batch meant for the web.
• Confirm before sending — select a file and press Command+I; the Kind line names the format outright if you ever want to double-check.

Seeing .heic is also your cue to convert. Once you know which photos are the problem, you can turn them into JPEGs in seconds with Preview or Quick Actions — no third-party app needed.

Turn the HEICs into JPEGs

Now that you can spot them, convert the HEIC files without changing your camera settings. Our walkthrough on converting HEIC to JPG on Mac covers the one-click Quick Action and a batch method for whole folders.