What is HEIC? The iPhone photo format

HEIC is the file format iPhones use for photos by default. It is Apple's name for HEIF images compressed with HEVC (H.265), and it stores a photo in roughly half the space of a comparable JPG. HEIF (High Efficiency Image File Format) is an image container standard from MPEG, published as ISO/IEC 23008-12. HEVC is the video codec doing the actual compression. When Apple pairs the two, the file gets the .heic extension. You will also see .heif, which is the same container family, though .heic is what iPhones write. In short, it is a modern, efficient photo format that is less universally supported than JPG, built on an open standard with licensed compression inside.

iPhones use HEIC because it saves storage without a visible quality penalty in normal viewing. Apple made it the default camera format with iOS 11 in 2017. A HEIC photo is typically roughly half the size of a JPG at similar visible quality, which adds up across thousands of photos and iCloud backups. The format also does things JPG cannot. It supports 10-bit color, where JPG is limited to 8-bit. It can hold multiple images in a single file. It can carry depth data, which powers Portrait mode edits. And it supports transparency. JPG has none of these features, so Apple gets better files and smaller storage from the same sensor. The tradeoff is compatibility, which is where most people first run into HEIC.

The main difference is efficiency versus compatibility. HEIC compresses better and carries more data, while JPG opens almost everywhere. A JPG is 8-bit, one image per file, no transparency, and compressed with a codec from 1992 that every browser, app and printer understands. A HEIC is usually smaller for the same visible quality, can hold 10-bit color, depth maps and several images, but depends on HEVC decoding. That decoder is the sticking point. HEVC is covered by patent licensing, which is why Windows needs an extension to open .heic files and why most web browsers cannot display them at all. Email recipients, upload forms and older software often reject them too. If a photo only needs to be viewed and shared, JPG is the safe choice. If you are archiving on an iPhone, HEIC is the better use of storage.

PixelTools decodes a HEIC in your browser into a PNG before doing anything else with it. The reason is simple: an img tag cannot show a raw HEIC in most browsers, so the file has to be converted to something the browser understands first. We use the heic2any library for this step, and the same decode path feeds our compressor and our image-to-PDF tool. While decoding runs, the preview shows a placeholder, and the real thumbnail replaces it once the PNG is ready. When you drop in a batch, the files are decoded one at a time rather than all at once. Decoding every file simultaneously would keep every decoded bitmap in memory together, which adds up fast with full-resolution iPhone photos. Going sequentially is slightly slower but far more reliable.

Colors can shift because iPhones capture in Display P3, a wider gamut than the sRGB that most JPGs and screens assume. If a converter relabels the pixel values as sRGB instead of remapping them, saturated reds and greens can look off. Display P3 covers a noticeably wider range of colors than sRGB, so a photo that looked rich on your iPhone can look different after conversion if the color profile is handled carelessly. This is a conversion issue, not a flaw in HEIC itself. A correct conversion maps P3 values into sRGB, accepting that some of the most saturated colors must be clipped or compressed. Our article on why HEIC to JPG colors look different walks through the cause and the fix in more detail. If color accuracy matters, compare the original and converted image on the same screen.

To open a HEIC, convert it to JPG or PNG, or install the right codec. On a Mac, Preview opens .heic natively. On Windows, you need the HEVC video extension and the HEIF image extension from the Microsoft Store. In a browser, a converter such as the PixelTools HEIC to JPG tool does it without installing anything. To stop your iPhone creating HEIC in the first place, go to Settings, then Camera, then Formats, and choose Most Compatible. New photos will then be saved as JPG. Existing photos stay as they are, and you will use more storage per photo. High Efficiency is the option that keeps HEIC. A related format worth knowing is AVIF, the royalty-free sibling built on the AV1 codec instead of HEVC, which browsers support far more widely.