Why iPhone photos are HEIC
Since iOS 11, iPhones save photos as HEIC (High Efficiency Image Container) by default. HEIC uses the HEVC video codec to store a photo in as little as half the space of a comparable JPG, which is why your camera roll fits more pictures.
The catch is compatibility. Many Windows apps, older Macs, web upload forms, and online services still expect JPG. Converting gives you a file that opens anywhere without asking the recipient to install anything.
Quality and file size
JPG is less efficient than HEIC, so a converted photo is usually larger than the original even though it contains no extra detail. At 92% quality the difference from the HEIC is not visible; lower the quality if you need smaller files for email or uploads.
The converter writes the image pixels only. Camera metadata such as location (GPS) is not copied into the JPG, which is useful when you are sharing photos publicly.
- 92% — visually identical, best for keeping
- 80% — noticeably smaller, still sharp for sharing
- Below 70% — use only when a size limit requires it
Stop your iPhone saving HEIC
If you always need JPG, open Settings → Camera → Formats and choose Most Compatible. New photos will be saved as JPG. Photos you have already taken stay HEIC, so a converter is still the quickest way to share those.