What is a HEIC file?
If you move photos off an iPhone and suddenly see files that will not open, it is almost always the format. The extension reads .HEIC.
A container, not an image
HEIC stands for High Efficiency Image Container. Apple has used it since iOS 11, so since 2017. Inside sits the picture, compressed with a method originally built for video. The result is roughly half the file size at the same visible quality. On the iPhone you never notice, because everything there can read it.
Why Windows stalls
Windows knows the format but does not ship the decoder. That is why File Explorer shows no thumbnails and a double click opens nothing. Your photos are not broken: the file is complete, the computer just cannot read it.
Two ways out
Either you teach Windows the format — the Microsoft Store has the HEIF Image Extensions, which in turn need the paid HEVC Video Extensions — or you convert the photos once to JPG, after which every program on every device opens them, today and in ten years.
Convert HEIC photos to JPG — right in your browser
Switch off the wifi before you start if you like. It keeps working — the conversion happens inside this window.
Select photos