If you are using Retina display you can see, that original 16x16 pixel favicons are pixelated. To make your Favicons Retina-ready you should export an .ico file in both 16x16px and 32x32px versions.
Using Faviconer.com you can create multi-resolution favicon that will automatically detect browser resolution and display proper icon size. You can draw a new icon from scratch or you can upload any graphic image and convert it to .ICO format.
More than 50% of top 50 global sites are already using 32px x 32px retina favicons.
As you can see, there are many advantages to have Favicon icon. Use our tool to create your custom favicon.
We suggest you to avoid PNG or GIF in any case, if you want reliable browser compatibility.