What is an ICO file?
ICO is the icon format of Windows and the classic format for website favicons, the small icon shown in browser tabs and bookmarks. Many hosting panels, CMS settings and Windows shortcut dialogs ask specifically for a .ico file. PNG, by contrast, is a general image format – converting bridges the gap.
Tips for good icons
Start with a square PNG, ideally with a transparent background – transparency is kept in the ICO. Icons are displayed very small, often 16 or 32 pixels, so simple shapes and strong contrast work best; fine text becomes unreadable. A non-square image may look stretched or have margins as an icon.
How to create your ICO
Drop your PNG above, ICO is already selected. Click “Convert” and download the .ico file. ImageMagick runs right in your browser, nothing is uploaded. Then upload the file to your website as favicon.ico or select it in Windows.