How can I convert png to ico without losing quality?

ICO is used by Microsoft apps. For beginners who prefers a simple and fast way to convert png to ico on a PC or Mac, then you can refer to this Microsoft guide for more details.

For advanced users, you can use the built-in Automator workflow for converting .png to .ico on mac.

However, you need to download and install the free image converter magic library first via homebrew.

You can use the built-in Automator workflow for converting .png to .ico on mac. However, you need to download and install the free image converter magic library first via homebrew.

After that, Automator → New Document → Quick Action.

Set Workflow receives: image files in Finder.

Add Run Shell Script to batch convert png to ico.

• Shell: /bin/zsh (or /bin/bash)
• Pass input: as arguments

# Converts each selected PNG to a multi-size .ico next to original.
# Requires: ImageMagick (`brew install imagemagick`)
set -euo pipefail

for f in "$@"; do
  # Only process PNG files; skip others silently
  case "${f:l}" in
    *.png)
      out="${f%.*}.ico"
      magick "$f" -define icon:auto-resize=256,128,64,48,32,16 "$out"
      ;;
    *)
      ;;
  esac
done

macOS Preview can't export directly to .ico, but you can export as .icns (Apple icon format) and then convert that to .ico using FFMPEG, an excellent free tool for video and images conversion, its support for Windows icon (.ico) format quite well.

Steps to convert PNG to ICO on Mac:

Open PNG in Preview → File > Export... → choose ICNS format.

Then convert .icns to .ico via:

ffmpeg icon.icns icon.ico

✅ Pros:

• No installation needed
• Quick for one-off PNG to ICO conversions

About PNG to ICO, the quality loss you're experiencing happens for two main reasons:

• ICO files require multiple resolutions - online converters often just scale your single PNG to these sizes poorly
• Poor resampling algorithms in basic converters

The Preview + Terminal method is excellent for creating macOS app icons (.icns), but for Windows .ico files, dedicated PNG to ICO converter tools will save you time and frustration while delivering the same (or better) quality results.

Here are some steps of using Preview + Terminal for Converting PNG to ICO:

1. Use Preview to create PNG files at each required size

2. Use iconutil in Terminal. iconutil is a macOS command-line tool used to create or convert Apple icon files (.icns). It’s built into macOS and primarily designed for macOS app developers who need to bundle icons for their apps.

bash
iconutil -c icns iconset.iconset

(Requires creating a special .iconset folder structure first)

Sorry, double posts.