ICO ↔ PNG Converter

What is an ICO file?

ICO (Icon) is a file format developed by Microsoft for Windows icons. An ICO file is a container that holds multiple image frames at different resolutions — typically 16×16, 32×32, 48×48, and up to 256×256 pixels. Windows picks the appropriate frame size depending on where the icon is displayed (taskbar, desktop, file explorer, etc.). On the web, ICO files are used as favicons — the small icon shown in browser tabs.

ICO → PNG: extract the largest frame

This tool extracts the largest image frame from the ICO file and converts it to PNG. If the ICO file embeds its images as PNG internally (common in modern ICO files), the PNG is extracted directly with no quality loss. Older ICO files use BMP internally, which the browser decodes and re-encodes as PNG.

PNG → ICO: multi-size favicon generation

To generate an ICO file, upload a PNG and select which sizes you want included. The tool uses to-ico, an open-source library, to package the resized frames into a single ICO container. For a standard website favicon, include at least 16×16 and 32×32. For a Windows application icon, include 16, 32, 48, and 256.

Why developers search for this

Generating a proper multi-size ICO from a PNG logo is a step almost every web project needs at least once. Design tools export PNG or SVG, but browsers and Windows expect ICO for favicons. Converting in the opposite direction comes up when extracting icons from older Windows software or recovering the original icon from a compiled executable.

Privacy

Conversion runs entirely in your browser. The ICO parsing and PNG/ICO encoding use the HTML Canvas API and the to-ico library — no server is involved.