PNG to ICO Converter

Create Windows-compatible ICO files from your PNG images. Generate multi-resolution favicon files that work perfectly for desktop applications and browser tabs.

Understanding ICO Files

The ICO format is a container that can hold multiple images at different resolutions and color depths. When Windows needs to display an icon, it selects the most appropriate size from the available options. This ensures icons look sharp whether displayed in a taskbar (16px), on the desktop (48px), or in a file manager large icon view (256px).

Recommended Sizes

For comprehensive Windows compatibility, include these sizes in your ICO file:

Web Favicons

For website favicons, you typically need fewer sizes. Modern browsers support PNG favicons, but including an ICO file ensures compatibility with older browsers:

• favicon.ico – Include 16×16 and 32×32 for browser tabs
• apple-touch-icon.png – 180×180 for iOS home screen
• favicon-32x32.png – Modern browsers
• favicon-16x16.png – Smaller tab displays

Preparing Source Images

Starting with High Resolution

Always start with the largest size you need (typically 256×256 or larger) and scale down. Starting with a small image and scaling up results in blurry icons.

Square Images

Icons must be square. If your source image isn't square, it will be cropped or padded. For best results, prepare a square source image before conversion.

Transparency

PNG files with alpha transparency convert correctly to ICO format. The transparent areas will remain transparent in the resulting icon file.

Technical Details

Color Depth

Modern ICO files use 32-bit color (24-bit color plus 8-bit alpha channel). This provides full color support and smooth transparency. Older systems may have used 8-bit or 4-bit icons, but these are rarely needed today.

File Size Considerations

Including many sizes increases file size. For web favicons, balance compatibility with file size—a favicon.ico containing just 16×16 and 32×32 is typically under 5KB. Application icons with all sizes from 16×16 to 256×256 may be 50-100KB or more.

PNG vs BMP in ICO

ICO files can store images in either BMP or PNG format internally. PNG compression significantly reduces file size, especially for the larger sizes. Our converter uses PNG compression for sizes 48×48 and larger, and uncompressed BMP for smaller sizes (as some older systems don't support PNG-in-ICO for small icons).