Setting the policy lets you set a list of URL patterns that specify sites that may display images.
Leaving the policy unset means DefaultImagesSetting applies for all sites, if it's set. If not, the user's personal setting applies.
For detailed information on valid url patterns, please see https://cloud.google.com/docs/chrome-enterprise/policies/url-patterns. * is not an accepted value for this policy.
Note that previously this policy was erroneously enabled on Android, but this functionality has never been fully supported on Android.