What the HEIC conversion actually tested
Our generated HEIC fixture is 1,913 bytes. The tool decoded it to a 320×240 still image and produced the JPEG listed below. This verifies this fixture, not every iPhone capture or HEIC variant. Keep an original that fails to decode; an unsupported decoder variation does not establish that your photo is damaged.
HEIC conversion loads an additional decoder when first used. Its first network request is for software, not an upload of your chosen photograph. A failed software download and an unsupported image are different problems. Retry a completed file in a supported browser, or export a JPEG with a compatible application. Apple describes HEIF conversion in its HEIF and HEVC support guidance.
A reproducible conversion result
Measured with the actual ExactKB compressor in Chrome 155.0.8059.84 on macOS, using decimal units, automatic dimensions and no size preset. Encoder percentages are settings, not measured detail retention. Results vary with the image and browser. Files are synthetic, contain no customer images, and are available below so you can reproduce the comparison.
Download the original test file. Select JPG, the 100 KB target, decimal units and Automatic dimensions. The fixture is synthetic, not a real camera photograph.
On a narrow screen, scroll the results table sideways to see all columns.
| Input / target | Output bytes | Output pixels | Encoder setting | Inspect file |
|---|---|---|---|---|
| Generated HEIC / 100 decimal KB / JPG | 8,043 | 320×240 | 95% | Download output |
This conversion increased the file from 1,913 to 8,043 bytes. JPEG is useful here for format compatibility; switching formats does not always reduce bytes.
Conversion is not a filename change
Download the result as a new image and reopen it. Changing an extension from .heic to .jpg does not perform conversion. Compare orientation, bytes and output dimensions. A small JPEG might retain all dimensions at the highest tested setting; the tool does not pad it up to your cap. A large image can instead shrink. The 100 KB target is only a starting point: select the actual limit and format your destination permits.
Motion, depth information and original metadata are not preserved by this still-image workflow. Keep your original before trying another target.
HEIC troubleshooting · Understand the 100 KB byte limit · Local processing and privacy