Why convert HEIC to JPG
HEIC is what an iPhone saves by default, and it is genuinely good: roughly half the size of a JPEG at the same quality, with support for depth information and a wider range of brightness. The trouble is that almost nothing outside Apple's own software reads it. Windows needs a separate codec from the Microsoft Store, most upload forms reject it outright, and many photo printers simply will not see the file. JPG is the format everything accepts, which is why this is the conversion people need most.
What this conversion costs you
- Depth and HDR information. HEIC can store a depth map and an HDR gain map alongside the picture. JPEG has nowhere to put either, so portrait-mode depth data and the extra brightness range are discarded. The visible picture is unaffected on an ordinary screen.
- Live Photo motion. If the photo is a Live Photo, only the still frame converts. The short video attached to it is not part of the image and does not survive.
- A second round of lossy compression. HEIC is lossy and so is JPEG, so a small amount of further detail is discarded in the re-encode.
When not to do this
Do not convert your only copy if the photo is a portrait-mode shot you may want to re-edit — the depth map that lets you change the background blur is lost. Keep the HEIC and convert a copy.
Common questions
Why can't Windows open my iPhone photos?
Windows does not include a HEIC decoder by default; the codec is a separate download from the Microsoft Store. Converting to JPG avoids the problem entirely and works everywhere.
Does this upload my photos to a server?
No. No browser except Safari can read HEIC on its own, so a one-time decoder downloads to your browser the first time you drop one of these files. The decoder comes to your device; your photo never leaves it.
Will the JPG be much larger than the HEIC?
Typically around twice the size, because HEIC compresses far more efficiently. That is the cost of a format everything can open.