HEIF to ICO: conversion guide

What happens when you convert HEIF to ICO?

Is HEIF → ICO right for you?

HEIF to ICO conversion details

Multiple source images

HEIF can contain multiple image representations with different roles. These are not automatically a timed animation. Selecting an image, preserving a collection or creating several outputs needs explicit engine support; neither a first-image choice nor an all-images export is implemented.

Animation becomes a still

An animated HEIF has a timed sequence; ICO is a still-image destination in this workflow. A still export loses motion and timing. Frame choice, blending and disposal must be defined by the future engine; a first-frame export is not promised.

HDR to SDR

If HDR source content is exported through an SDR representation, it needs a display rendering. Values outside the output range require tone mapping, scaling or clipping; brightness relationships can change. Tone mapping, exposure and colour handling depend on the future engine. Renaming or lossless compression cannot preserve out-of-range values.

Icon packaging

ICO can package alternative icon sizes and image encodings. Converting one image does not automatically design a readable small icon or generate every required size. Resampling, image entries, alpha/mask representation and encoding are future engine choices; check the target application’s icon requirements.

Transparency representation

Both format profiles allow transparency, but this does not promise identical alpha representation. Source variants, target channel precision and alpha interpretation matter. The future encoder must explicitly carry or convert transparency; merely choosing ICO guarantees no alpha transfer.

Encoding mode

ICO compression depends on the embedded image payload. Multiple sizes are alternatives, not animation frames; transparency handling differs between old masks and alpha-capable images. ICO permits different encoding modes or container representations. Its format name alone does not promise lossless output, a quality setting or a size reduction. The future engine must choose a supported codec and sample representation; inspect the target’s compression notes below.

Sample precision & colour

Source and target sample models can differ in precision, channel layout, colour space and transfer function. Lossless compression only preserves the samples actually encoded; a precision reduction or colour conversion can already change them. The future engine defines numeric mapping, orientation and colour conversion; canonical depth facts are listed below where available.

Metadata & colour

Format support does not guarantee that an export preserves metadata or colour profiles. Retention and colour handling depend on the future converter; its engine is not implemented yet.

Compression

HEIF: Depends on variant → ICO: Depends on variant HEIF: HEIF defines the container. Compression may be lossy, lossless or uncompressed depending on its codec binding; one global quality or bit-depth value would be misleading. ICO: ICO compression depends on the embedded image payload. Multiple sizes are alternatives, not animation frames; transparency handling differs between old masks and alpha-capable images.

Transparency

HEIF: Yes → ICO: Yes

Animation

HEIF: Yes → ICO: No

Colour depth

HEIF: Codec/profile dependent

HDR

HEIF: Codec/profile dependent

Multiple images

HEIF: Collections & sequences → ICO: Alternative icon sizes

Dimensions

Pixel dimensions, page geometry, rendering resolution, resizing and orientation need explicit converter policies. The future engine has not defined them yet.

Metadata

HEIF: Exif, XMP, ICC, NCLX → ICO: Image dimensions, Colour depth. Which fields are copied, rewritten or omitted will depend on the future engine; retention is not implemented yet.

Common questions