Why Won't My iPhone Photos (HEIC Files) Open on Windows or Other Devices?
Sending yourself a photo from an iPhone and finding it won't open — or shows as a generic file icon with no preview — is one of the most common cross-device photo headaches, and it isn't a sign anything's actually wrong with the photo. It's a format that iPhones use by default, that a lot of other software simply doesn't recognize yet.
What HEIC actually is
HEIC (High Efficiency Image Container) has been the default photo format on iPhones since iOS 11, chosen because it produces meaningfully smaller files than JPG at a comparable visual quality — genuinely useful given how many photos a phone camera generates. The tradeoff is that HEIC is newer and far less universally supported than JPG, which has been the de facto standard for decades and is recognized by essentially everything.
Why it fails to open elsewhere
Recent versions of Windows, most browsers, and a lot of third-party photo software either don't support HEIC at all, or need an additional codec installed before they will — support has been improving, but it's still noticeably behind JPG's near-universal compatibility. The photo file itself isn't damaged; the application trying to open it simply doesn't know how to decode that particular format, which is why it often shows a blank thumbnail or a generic file icon instead of an actual error.
The quickest fix without changing anything on your iPhone
iPhones can be set to always save photos as JPG instead of HEIC (in Settings → Camera → Formats → "Most Compatible"), which prevents the problem going forward — but that doesn't help with photos you've already taken, and some people prefer keeping HEIC's smaller file sizes for storage on the phone itself while only needing JPG occasionally, for a specific recipient or upload. For existing photos, converting them to JPG on the way out solves the immediate problem without changing how the phone captures new ones.
What actually happens during conversion
Converting HEIC to JPG re-encodes the image data into the older, more compatible format. Because HEIC's compression is generally more efficient than JPG's, the resulting JPG is often somewhat larger in file size than the original HEIC for an equivalent visual quality — the point of converting is compatibility, not smaller files, which trips some people up when they see the file size go up rather than down.
HEIC to JPG converts iPhone photos to universally-compatible JPG files directly in your browser, including batches of multiple photos at once, without needing to change any settings on the phone itself.