What file of what size is used on your device?

Hey! Read my recommendation (updated august 2020)

Here is the possibilties:

1. A favicon.ico in the root, which is not mentioned in the html

favicon.ico 16x16 (png) favicon.ico 24x24 (png) favicon.ico 32x32 (png) favicon.ico 48x48 (png) favicon.ico 96x96 (png) favicon.ico 128x128 (png) favicon.ico 256x256 (png)

2. A png icon, with a 512x512 image (size not specified)

<link rel="shortcut icon" type="image/png" href="shortcut-icon.png">

3. A png icon, with a 16x16 image (size specified)

<link rel="icon" sizes="16x16" type="image/png" href="icon-16x16-specified.png">

4. Apple-touch-icon, with a 512x512 image (size not specified)

<link rel="apple-touch-icon" href="apple-touch-icon-512x512-unspecified-size.png">

5. Apple-touch-icon, with a 512x512 image

<link rel="apple-touch-icon" sizes="512x512" href="apple-touch-icon-512x512-specified.png">

6. MsApplication-TileImage for Win10, with a 512x512 image (size not specified)

<meta name="msapplication-TileColor" content="#FF7F00" /><!-- ORANGE -- >
<meta name="msapplication-TileImage" content="msapplication-tileimage-512x512-unspecified-size.png">
msapplication tileimage win10 512x512 unspecified size TileColor #FF7F00 (orange)