What the converter does to a HEIC file
HEIC to JPG converter reads a HEIC or HEIF file and writes a JPG from it. The tool has no settings: the quality is fixed at a high value, the pixel dimensions stay those of the original, and nothing is scaled, padded or cropped. The decoding is done by an open-source library that is served from this site and loaded when the first file is dropped, so the photo is converted on the device and is not sent to a server.
Several files can be dropped together. They are converted one after another, and each gets a card with a status line, the weight of the new JPG, a preview and a download link. The JPG keeps the name of the original with the new extension. A file that cannot be read as HEIC gets a message in its card, and the run continues with the next file.
When conversion is the step, and when it is not
Conversion is the step when a phone saved the photo as HEIC and the place it has to go does not take that format. Not every sales channel refuses HEIC, so the format list on its rule page is worth a look first. The other free tools work on a file only when the browser can open it; where the resizer or the compressor reports that it cannot open a photo, its message points to this converter.
The converter changes the file format and leaves the framing and the pixel size as they were. A JPG that has to meet a pixel size goes to the Marketplace image resizer, and one over a file-size limit goes to the Image compressor. Herofab's tools work on the image itself: Remove background puts the product on a transparent, white or light grey ground, Upscale raises the resolution, and Extend frame gives an image a new shape without cropping.
Checking the JPG before it is uploaded
The status line gives the weight of the JPG. It is often heavier than the HEIC it came from, because HEIC stores a photo in a smaller file at similar quality. The preview shows the converted picture: compare its orientation and its colours with the original, above all for a product whose exact shade matters.
The JPG is a new file, and the camera details or the location stored in the HEIC may not be carried over into it, so the original is the copy to keep where that information matters. The tool measures nothing: size and format rules are compared by the Image size checker, background and framing by the Product photo checker, and the sales channel's rule page is the last word.