Site Logo: Add preview when image used as Site Icon

[westonruter]

What problem does this address?

The Site Logo block allows for the selected image to also be set as the Site Logo. Nevertheless, the description for that toggle does not indicate that the Site Icon is square, and it does not indicate that the selected image will be cropped to become square. Contrast this with the Site Icon control in the Customizer where there is a preview showing how an image will be cropped as a square and where it will show up in a mock browser UI.

What is your proposed solution?

• When the "Use as site icon" toggle is checked, that the same Site Icon preview from the Customizer be rendered below the toggle.
• The copy should also be updated to note that the icon is a square and what its dimensions are.
• Show a warning when the Site Logo will end up being cropped to be less than 512 pixels square.
• (Out of scope) Optionally provide a UI to do a custom crop of the Site Logo or to select an entirely different image to be used as the Site Icon. Maybe this gets into a larger architectural question about managing global settings in the Site Editor.

Current Site Logo Block	Current Site Icon in Customizer

[wparasae]

Related issue: WordPress/Learn#512 (comment)

[richtabor]

) Optionally provide a UI to do a custom crop of the Site Logo or to select an entirely different image to be used as the Site Icon.

Perhaps so — currently the Site Icon is not cropped, if it's added within by the Site Logo block.