A camera roll is not a file. It is a few hundred files, usually between one and four gigabytes, and it is the moment the average online converter shows its business model: upload everything, wait, discover the free tier converts five, decide whether to pay or start over somewhere else.
The trap in the free-tier model
Converting on a server costs someone CPU, transfer and storage, so the services either meter it or advertise it and monetize elsewhere. The metering is the part that stings: a size cap per file, a count cap per visit, a queue that puts anonymous users last during peak hours, and a privacy policy that governs the one thing you cannot verify from outside — when the uploads are actually deleted.
What batch conversion looks like in the browser
The HEIC converter has no server in the loop, so none of those limits exist. Select the whole folder — Finder, Explorer or the Photos picker — drop it, and the queue processes files one at a time. A 12-megapixel photo needs about 48 MB of memory while it is being decoded, released immediately after, so a few hundred files run on any recent laptop without strain; the pace lands around a file per second on a modern machine, decoder loading included. When the set is done, one button packs everything into a zip.
The macOS shortcut worth knowing
If you live in the terminal, sips — the built-in scriptable image tool — converts a directory without any app at all:
- cd into the folder, then run: for f in *.HEIC; do sips -s format jpeg "$f" --out "${f%.HEIC}.jpg"; done
- sips keeps EXIF and leaves orientation to the tag, which desktop viewers honour; the browser route normalizes orientation into the pixels, which web tools and print shops prefer.
- On Windows there is no equivalent built-in; the browser route above covers it without installing the HEIF extensions.
Stopping the problem at the source
New photos: iPhone Settings → Camera → Formats → Most Compatible writes JPEG from then on, at the cost of larger originals. It does nothing for the photos already on the phone, which is exactly the pile most people are here for. Convert that pile once, keep the HEIC originals in an archive folder — they carry slightly more data for future editing — and let the JPGs do the travelling. For the reverse question, whether renaming .heic files to .jpg achieves anything at all, it does not, and the reason has to do with what is inside the container rather than what it is called.