You pull a photo off your iPhone over a cable and the file that lands is not IMG_4021.JPG — it is IMG_4021.HEIC, and half the software on the machine refuses to open it. That is not a bug, and the download is not corrupted. Since iOS 11, iPhones have captured photos in HEIF rather than JPEG by default, and the HEIC vs. JPG difference is a deliberate trade Apple made: smaller files at the same visual quality, in exchange for a format the rest of the world was slower to support.
Here is what a HEIC file actually is, what the switch buys you, the settings that control it, and when you are better off just shooting JPEG.
What a HEIC file actually is
HEIF stands for High Efficiency Image File Format, standardised as ISO/IEC 23008-12 and first published in 2017. Crucially it is a container, not a codec — the same way an .mp4 is a box that video and audio tracks sit inside. HEIF can hold image data compressed by several different codecs. When the image inside is encoded with HEVC (also called H.265), the file takes the .heic extension. That is the flavour your iPhone writes.
Being a container is the interesting part. One HEIF file can hold more than a single picture, plus auxiliary data attached to the main image — alpha channels, depth maps, thumbnails — plus non-destructive edits stored as instructions referencing an untouched original. A JPEG is one image and some metadata, full stop. That difference is why a Live Photo, a depth map and a burst can sit in your Photos library in a way a folder of JPEGs cannot represent.
Why Apple switched, and what it buys you
Compression efficiency, almost entirely. JPEG's coding dates to the early 1990s; HEVC intra-frame coding is roughly two decades newer and predicts far more of each image from what it has already decoded, so it needs fewer bits for the same picture.
Nokia, which developed HEIF, reports in its technical documentation that JPEG requires on average 139 percent higher bitrate than HEVC — about 2.39 times the file size — for the same objective picture quality. Apple puts it less precisely: HEIF and HEVC offer better compression than JPEG and H.264, so they use less storage space on your devices and iCloud Photos, while preserving the same visual quality.
Treat roughly half the size as a ceiling rather than a promise. How much you actually save depends on the picture — smooth skies and skin tones compress dramatically better, dense noisy detail much less so. The honest summary: a HEIC photo is usually meaningfully smaller than a JPEG that looks the same, and across several thousand photos that adds up.
The two iPhone settings that control it
There are two separate settings, and mixing them up is the usual reason people believe they turned HEIC off and it came back.
- Capture format.
Settings > Camera > Formats. High Efficiency captures HEIF and HEVC; Most Compatible captures JPEG and H.264. Apple notes this option appears only on devices that can capture HEIF — per its documentation, iPhone 7 and later, iPad (6th generation), iPad Air (3rd generation), iPad mini (5th generation) and 10.5-inch iPad Pro and later, running iOS 11 or later. - What happens on USB transfer. Apple's current instruction is
Settings > Apps > Photos, then scroll down and tap Keep Originals. In iOS Settings this sits under a Transfer to Mac or PC heading, where the other choice is Automatic: Automatic converts to JPEG and H.264 on the way out when the receiving computer needs it, Keep Originals hands over the untouched HEIC. TheSettings > Appspath is the iOS 18 and later arrangement — earlier releases put the same control directly atSettings > Photos.
Worth knowing first: switching Formats affects only photos taken from that point onward. It converts nothing already in your library.
Where HEIC actually breaks
Apple quietly handles most cases for you. Its documentation says that when you share HEIF or HEVC media over AirDrop, Messages or email to a device or service that cannot handle it, the media might automatically be shared in a more compatible format, such as JPEG or H.264. That is why most people never meet a .heic file until they plug the phone into a computer or download originals out of iCloud.
When it does break, it breaks in three predictable places.
- Windows. HEIC is not decoded out of the box. Microsoft publishes a HEIF Image Extension in its Store, and that listing states the separate HEVC Video Extensions package must also be installed to view images stored in HEIF files using the
.heic,.hifor.heifextensions. Two dependent packages is often more hassle than converting the few files you needed. - The web. Browsers mostly do not decode HEIC. As of September 2026, Safari 17 and later is the only major browser with support; Chrome, Edge and Firefox have none. An
<img>tag pointing at a HEIC fails for most visitors, and upload forms that preview images in the browser usually reject the file before it is sent. - Older Android and older apps. Android added platform HEIF support in Android 9 (Pie), documenting encoding and decoding via
ImageDecoder,BitmapFactoryandHeifWriter. A current Android phone opens HEIC fine. Individual apps that handle images themselves — older uploaders, some scanners, plenty of workplace software — may still not.
On a Mac there is nothing to fix: Apple states HEIF and HEVC support is built into macOS High Sierra 10.13 and later. For a JPEG copy, open the file in Preview, choose File > Export, then pick JPEG from the Format pop-up menu.
HEIC vs. JPG: does converting lose quality?
Yes, a little. The mechanism is worth understanding more than the outcome is worth worrying about.
The HEIC your iPhone writes is lossy — detail was already discarded at capture, when the photo was encoded. Converting to JPEG recovers none of it: the converter decodes the HEIC back to raw pixels, then re-encodes them with a second, different lossy codec. You are stacking one generation of loss on another. At normal quality settings the result is visually indistinguishable on screen, but it is not mathematically identical, and it will usually be a noticeably larger file for that same appearance, because JPEG is the less efficient format.
Two rules follow. Convert once, from the original, not from something already round-tripped through another format. And keep the HEIC if you have the storage — it is the closest thing you have to a master. If the JPEG then needs to be smaller in bytes, do that deliberately with a compressor rather than by re-saving repeatedly; How to Compress Images Without Losing Quality covers where the visible threshold sits. Smaller in dimensions is a different operation again, covered in Why Images Get Blurry When You Resize Them.
When to just shoot Most Compatible instead
Most Compatible suits a narrower group than the internet suggests, but that group is real:
- Your photos routinely land in a Windows workflow, a web CMS, or software you do not control.
- You hand photos to other people — a client, an insurer, a school — and cannot troubleshoot their computer for them.
- You shoot very little, and storage has never been a constraint you thought about.
For everyone else, staying on High Efficiency and converting the few photos that need to leave the Apple ecosystem is the better trade: you keep the saving across thousands of photos and pay the conversion cost only on the handful.
The HEIC to JPG converter here does that step in your browser, with nothing sent to a server. That matters more than usual for photos: HEIC files from a phone routinely carry Exif metadata including capture time, device model and, if location services were on, GPS coordinates — all of which a server-side converter receives with the picture. If you want that data gone as well as the format changed, check the output in an Exif viewer rather than assuming a converter strips it.
Runs entirely in your browser — your photos are never uploaded anywhere.
Open HEIC to JPG →Frequently asked questions
Because High Efficiency is the default capture format. Since iOS 11, iPhones that support it save photos as HEIF (with the .heic extension) rather than JPEG, because HEIF stores comparable visual quality in a smaller file. You can change it at Settings > Camera > Formats by choosing Most Compatible, which switches capture to JPEG and H.264 for photos taken from then on.
Windows does not decode HEIC out of the box. You can install Microsoft's HEIF Image Extension from the Store, though its own listing notes the separate HEVC Video Extensions package is also required for .heic files. For a handful of photos it is usually quicker to convert them instead — a browser-based converter does it locally without installing codecs. Alternatively, set the iPhone itself to convert on transfer via Settings > Apps > Photos, which is the Automatic option under Transfer to Mac or PC.
Modern Android can. Android 9 (Pie) added platform-level HEIF support, including decoding through ImageDecoder and BitmapFactory, so a current phone's gallery opens .heic normally. Older devices, and individual apps that handle images themselves rather than using the platform decoder, may still refuse the file — in which case converting to JPEG is the reliable fix.
Slightly, yes. HEIC is already a lossy format, so converting decodes it and re-encodes with a second lossy codec — a second generation of loss. At normal quality settings the difference is not visible on screen, but the JPEG is not identical to the HEIC and will usually be a larger file for the same apparent quality. Convert once from the original, and keep the HEIC if you have room for it.