What actually happens when you convert HEIC to JPG

What HEIC is

HEIC is a HEIF file — High Efficiency Image File Format — containing an image compressed with HEVC, the video codec also known as H.265. Apple made it the default camera format in 2017.

The reasoning is the same as with AVIF: a modern video codec compressing a single frame beats a 1992 still-image codec by a wide margin. A HEIC photo is typically about half the size of the equivalent JPEG at the same visual quality. On a phone holding several thousand photos, that is a meaningful amount of storage.

HEIF is also a container, not just an image. A single .heic file can hold multiple images, which is how Live Photos and burst shots are stored, along with depth maps, edits that can be reverted, and image metadata.

Why it does not open anywhere

HEVC is patent-encumbered. Decoding it requires licensing, and that licensing cost is why support did not spread the way JPEG's did. Apple platforms handle HEIC natively. Windows needs an extension from the Microsoft Store. Many web upload forms, content management systems, older photo software, and print services simply reject the extension.

This is a licensing and ecosystem problem, not a technical one, which is precisely why AVIF — royalty-free, built on AV1 — has better momentum outside Apple despite arriving later.

What converting to JPG costs you

Converting HEIC to JPG is a lossy-to-lossy conversion, so it is a second compression pass. In practice, at sensible quality settings and viewed normally, the difference is very hard to see. The photo is not visibly damaged.

What you do lose is everything HEIF carries that JPEG has no place for:

• The extra frames. A Live Photo becomes a single still. A burst becomes one image.
• Depth information. Portrait-mode depth maps do not survive, so you cannot re-adjust the background blur afterwards.
• Non-destructive edits. HEIC can store the original alongside an edit that can be undone; JPEG stores one flattened picture.
• HDR gain maps on newer devices, which is why a converted photo can look flatter on an HDR display than the original did.
• File size. A JPEG of the same photo at comparable quality is typically about twice as large.

Converting to PNG instead

People sometimes reach for PNG because it is lossless and therefore sounds safer. For a photograph it is the wrong choice. PNG is lossless, but the HEIC has already been through lossy compression, so there is no extra quality to preserve — and PNG compresses photographs poorly, so the file can end up five or ten times the size of the original HEIC while looking identical to the JPEG.

PNG is the right target when the HEIC is a screenshot, a diagram, or artwork with flat areas and hard edges. For a camera photo, JPG.

Stopping the problem at the source

If you keep running into this, change what the camera writes. On iOS: Settings → Camera → Formats → Most Compatible. The phone will shoot JPEG from then on. You lose the storage saving and the extra HEIF features, and you stop having this conversation.

There is also a middle path that most people miss: iOS already converts on export. If you share a photo through the standard share sheet to an app or a service, it usually hands over a JPEG automatically. The files that arrive as .heic are typically the ones copied directly off the device, pulled from a backup, or sent through something that requested the original.

The practical recommendation

Convert to JPG when you need to send a photo somewhere that does not accept HEIC. Keep the HEIC — it is the original, it is smaller, and it holds things the JPEG does not.

Do not convert your whole photo library "for compatibility". You would double its size to solve a problem that only exists at the moment of sharing, and you would permanently discard the depth data and Live Photo frames in the process. Convert the ones you are actually sending, when you send them.