LocalPixiPhone camera photos default to HEIC (HEIF). That file is smaller on the phone and awkward everywhere else: Outlook, a university portal, or a PDF form that says “JPG only.” LocalPix HEIC to JPG decodes the still with libheif-js WASM (LGPL-3.0), loaded only after you pick a file, then encodes JPEG on a canvas. Nothing is posted to a LocalPix upload API.
What to convert — and what to skip
- Camera stills named
.HEICor.HEIF— this tool. - Screenshots — iOS screenshots are usually PNG, not HEIC. Use Compress to KB or the PNG email guide instead.
- Live Photos — the still is the HEIC; the motion is a separate movie. Convert the still only.
- Already a JPEG — do not run it through HEIC decode. If it is only too large, go to attachment KB caps.
Steps
- On the iPhone, share or AirDrop the photo as the original HEIC (not “Most Compatible” if you already have a JPEG you are happy with). Copy it to the computer you will submit from.
- Open HEIC to JPG. Optional proof: Verify local and the homepage 0-byte upload checklist. Before you pick a file, libheif WASM should not download.
- Drop the HEIC. The ~1.4 MB WASM loads on demand, then the still decodes in the tab.
- Leave JPEG quality at 92 unless the form is already near a size cap. Encode and look at the preview.
- Download the
.jpg(localblob:URL) and attach that file — not the HEIC.
Pitfalls
- Orientation. Some HEIC files keep rotation in metadata rather than in the pixel buffer. If the preview is sideways or upside down, do not submit it. Rotate in any local editor and export JPEG again. A form that auto-rejects “wrong aspect” will not fix this for you.
- Quality vs size. 92 is sharp enough for most ID-style stills and too big for a 200 KB portal. Lower the slider only a little, or pass the JPG through Compress to KB and read the size the tool reports. Re-encoding twice softens text and hair.
- Rare HEIC variants can fail to decode (10-bit, unusual brands, or a file that is not a still). You get an on-page error — the bytes still have not been uploaded. Try another export from Photos, or a JPEG the phone already saved.
- Privacy of the phone backup is separate. iCloud already has the photo if you use iCloud Photos. LocalPix does not add a second upload. See Licenses for the libheif notice.
FAQ
Does my HEIC leave the device?
No. Decoding runs in the browser after you choose the file. Watch Network: libheif under /assets/libheif/ may load; your photo should not POST to the LocalPix origin. Steps: Verify local.
Why is the JPG sideways?
Rotation is sometimes stored beside the pixels. Trust the preview, not the filename. Fix orientation locally before you attach it to email or a form.
What quality should I pick?
Start at 92. Drop it only when the recipient named a KB cap, and prefer one pass through Compress to KB over several blind re-exports.
Related
HEIC to JPG · Compress to KB · Email attachment caps · ID photo background · Verify local