Warn when no Site Icon set, when it is too small, or when a PNG is not being used

[westonruter]

The Lighthouse PWA audit flags a Web App Manifest that:

1. Is lacking an icon.
2. Has an icon that is less than 512px square.
3. Is not a PNG.

These requirements should be enforced in the Customizer when selecting a site icon, and/or a warning notice should be shown with the Customizer control when the selected icon does not satisfy the requirements. This should also be added as a Site Health test.

[gziolo]

I run into this issue on my site that had an icon set a few years back. Related Twitter thread:
https://twitter.com/gziolo/status/1261338942328016896

[westonruter]

There should be a link from the Site Health test to the location where the Site Icon can be updated. As mentioned in #304 (comment), Full Site Editing complicates this a bit since block-based themes don't have the Customizer.

[ankitrox]

@westonruter I will take this up from here and will look into possibilities to handle the mentioned scenarios.

[westonruter]

In addition to the Customizer, this should be implemented as a Site Health check. See also:

pwa-wp/wp-includes/class-wp-web-app-manifest.php

Line 246 in 928905e

* @todo Add test for PNG site icon.

The test should then have as one of its actions a link to go to the Customizer or Site Editor to edit the site icon. See related change for short name test.

[pooja-muchandikar]

QA Passed ✅

Warning messages are shown as expected.

Screen.Recording.2022-04-19.at.7.02.31.PM.mov