- Choose one PNG — a sharp square image works best, and the background may be transparent.
- Check the preview. Rectangular images are centred with padding, not stretched.
- Click Create file and download the ICO.
Which sizes are included?
Each ICO contains seven sizes: 16, 24, 32, 48, 64, 128 and 256 pixels. Windows picks the size that suits where the icon is shown.
Why are small icons hard to see?
A 16-pixel icon has very little room. Use clear outlines, little text and a large subject; resizing cannot add detail the original lacks.
How do I keep a transparent background?
The input image itself must have a transparency channel; saving a white background as PNG does not make it transparent. Rectangular images are centred in proportion with padding around them, not stretched.
How should I check the icon?
Look at both a large size and the 16-pixel size. Thin text, complex shadows and fine lines may disappear in small icons, so simplify the outline. An ICO file is an icon resource; it does not modify an already-built software installer.