You get a photo from an iPhone user. Windows Photos shows an error, your Android gallery will not preview it, and the upload form rejects it. The file ends in `.HEIC` and nothing seems to want it.
Nothing is broken. It is a format problem with a straightforward fix.
What HEIC actually is
HEIC is Apple's name for an image stored in the HEIF container using HEVC compression. iPhones have shot it by default since iOS 11 in 2017.
The reason is genuinely good: HEIC files are roughly half the size of an equivalent JPEG at the same visual quality. It also supports 16-bit colour (JPEG is 8-bit), transparency, and multiple images in one file — which is how Live Photos and burst shots are stored.
The problem is licensing. HEVC is patent-encumbered, so support has to be paid for. That is why Windows asks you to buy a codec extension, why many Android devices skip it, and why plenty of web upload forms simply reject the extension.
Converting in a browser
The image converter handles HEIC to JPG and PNG. Because it runs in your browser, the photo is never uploaded to a server — which matters more than usual here, since HEIC files from a phone carry full EXIF metadata including GPS coordinates.
That is the main argument against the many "free HEIC converter" sites: you are handing a stranger a photo tagged with where it was taken.
Pick JPG unless you specifically need transparency. Nearly every system accepts JPG, and for a photograph the quality difference is invisible.
Stop it happening again
If you are the iPhone user, two settings changes fix this permanently.
Shoot JPEG instead of HEIC:
Settings → Camera → Formats → Most Compatible"High Efficiency" is HEIC; "Most Compatible" is JPEG. You lose the storage saving and gain the ability to send photos to anyone. For most people that is the right trade.
Or convert only when sharing:
Settings → Photos → Transfer to Mac or PC → AutomaticThis keeps HEIC on the device but converts to JPEG when transferring to a computer. You keep the storage benefit and avoid most of the pain.
A caution on AirDrop: it preserves HEIC between Apple devices, which is why the problem is invisible until someone sends a photo to a Windows or Android user.
Other routes
Windows — Microsoft sells "HEIF Image Extensions" in the Store. It works, and it is a per-machine fix that does not help when you forward the file to someone else.
Android — Android 10 and later can decode HEIC at the OS level, but gallery app support is inconsistent. Google Photos handles it; many manufacturer galleries do not.
Email or messaging — WhatsApp, Messenger and most email clients convert to JPEG automatically when sending. Handy in a pinch, but they also compress heavily, so quality drops.
macOS — Preview opens HEIC natively; File → Export saves as JPEG.
Live Photos and multi-image files
A Live Photo is a still image plus roughly three seconds of video. Converting it to JPG gives you the still frame only — the motion is discarded.
If the motion matters, keep the original. A converted copy cannot get it back.
Similarly, HEIC files from burst mode can contain several images. Converters typically extract the primary one.
After converting
A converted JPG is often larger than the HEIC it came from, because JPEG is less efficient. If you are converting to meet an upload limit, expect to compress afterwards.
The usual order:
1. Convert HEIC → JPG with the image converter 2. Resize if the dimensions exceed what is needed, using the image resizer 3. Compress to hit the size cap with the image compressor
That sequence is covered in more detail in getting an image under 100 KB.
Frequently asked questions
Does converting lose quality?
A little — HEIC and JPEG are both lossy, so re-encoding costs something. At default quality it is not visible for normal viewing.
Why is my converted JPG bigger than the HEIC?
JPEG is a less efficient codec. Roughly double the size for the same visual quality is expected.
Can I convert several at once?
The browser converter handles files one at a time. For a large batch, changing the iPhone camera setting is the better fix.
Is HEIC better than JPEG?
Technically yes — smaller files, more colour depth, transparency support. Practically, JPEG's universal compatibility usually wins.
Will HEIC files still open in ten years?
Almost certainly, given how many exist. But for archival photos you care about, JPEG or PNG is the safer long-term bet.
Related reading
Once converted, getting an image under 100 KB covers hitting hard upload limits without visible damage.