How to Convert HEIC to ICO in Your Browser

How HEIC becomes ICO

1. Your browser decodes the HEIC/HEIF container using its built-in HEVC image decoder, which returns one image per frame — a single photo, or a full array of frames for a burst or Live Photo.
2. Each decoded frame is resized independently into the standard icon resolutions (typically 16, 32, 48, and 256 pixels), preserving that frame's alpha channel at every size.
3. Every resolution is compressed as PNG image data and packed into an ICONDIR structure — the container format Windows expects an ICO file to use, with one directory entry per embedded size.
4. If the source HEIC held more than one frame, each frame produces its own complete multi-size ICO, and the full set is bundled into a ZIP so nothing from the original capture is dropped.

What changes when you convert

A HEIC photo is HEVC-coded — the same lossy compression family used for video — and decoding it hands the converter a plain raster frame with no further claim to the original compressed data. That frame is downsampled to each icon resolution and re-encoded as PNG, which is lossless, so the quality loss you should expect comes from shrinking a full-resolution photo down to 16 or 32 pixels, not from re-compression.

The one thing that doesn't survive is metadata: EXIF fields like camera model, capture date, GPS coordinates, and orientation are stripped during decoding. That matters if you were relying on HEIC's metadata as a record rather than just its pixels — the ICO output only ever carries image data.

The more consequential change is what happens with multi-image HEIC files. Live Photos and burst shots are HEIC containers holding several frames, and because each individual ICO is already a small multi-resolution package (16 through 256px in one file), a four-frame burst doesn't collapse into a single icon — it produces four separate multi-size ICO files, zipped together. Worth confirming which frame you actually want before converting a burst, since every frame gets the full icon treatment whether you need it or not.

When ICO is the right choice — and when it isn't

ICO exists for one purpose: giving Windows a single file that contains an icon at every size the operating system might need — a 16px version for a title bar, a 256px version for a high-DPI desktop shortcut — and letting Windows pick automatically. If your HEIC photo is destined to become an app icon, a desktop shortcut image, or a browser favicon, that's exactly the job ICO does, and no common web image format packages multiple resolutions into one file the same way.

But most people converting a HEIC photo aren't building a Windows icon — they're trying to open or share an iPhone photo somewhere that doesn't recognize HEIC. For that, ICO is the wrong target: it throws away almost all of the photo's original resolution (icons top out at 256px) and produces a file no photo viewer or social platform treats as a picture. Converting to WebP or PNG instead keeps the image at full size and is the better move if the actual goal is compatibility, not iconography.

Limitations and privacy

The conversion is a one-way pipeline: once the HEIC is decoded and downsized, neither HEVC's original compressed data nor the source's EXIF metadata carries forward, and there's no way to recover either from the resulting ICO. Small or low-contrast details in the source photo can also become illegible once shrunk to 16 or 32 pixels — a property of small icon sizes generally, not a flaw in this conversion.

Everything happens locally in your browser using its native HEIC decoder — the file is never uploaded to a server, which also means HEIC decode support and conversion quality depend on your browser rather than on Looty Tools' infrastructure.