Can I Compress HEIC Images with krzen.com?
No. krzen.com accepts JPEG, PNG, and WebP files only, and its file input does not list HEIC. Convert the photo to JPEG first, on the phone or in the Photos app, then drag the JPEG into the compressor. The output can be JPEG, PNG, WebP, or AVIF.
What the file input accepts
The compressor has one file input. Its accept attribute names three image types and nothing else:
<input type="file" id="file-input" accept="image/jpeg,image/png,image/webp" multiple>The word HEIC does not appear in the site source. A search of the whole repository returns zero files. So there is no HEIC decoder, no HEIC branch, and no fallback path.
Why iPhone photos are HEIC
An iPhone writes photos as HEIC by default. HEIC is a container for High Efficiency Image Format pictures. It keeps files small, but a browser cannot decode it the way it decodes JPEG, PNG, or WebP.
Convert the photo to JPEG
On the iPhone, open Settings, then Camera, then Formats, and choose Most Compatible. New photos are then written as JPEG.
For a photo that already exists, open it in the Photos app, tap Share, and choose an option that exports a JPEG, such as Mail or Save to Files. On a Mac, open the file in Preview, choose File, then Export, and select JPEG.
Do not rename photo.heic to photo.jpg. The name changes and the bytes do not. The compressor reads bytes, so a renamed file still fails.
After the conversion
A JPEG from an iPhone usually carries more bytes than the HEIC original. The compressor can remove those extra bytes. Set quality between 70 and 85 for a photo, or resize the image to the width it is shown at. Both controls are on the home page compressor. For format guidance see the image optimization checklist.
