When adding a default OpenGraph image there's no visual indicator if it'll be used

[kennydude]

Is your feature request related to a problem? Please describe.

I previously set a default OpenGraph image, and without any visual errors assumed it was working. When working through the Image class and how it decides if it will be displayed, it turns out the dimensions were not correct. Only after putting in an image with the exact dimensions, did it work as expected.

Describe the solution you'd like

A warning in the admin saying "This image does not meet the dimensions to be used as an Open Graph default image" or something like that.

Describe alternatives you've considered

Creating a from-scratch default image, which did work

Additional context

I don't think so, but happy to provide anything if needed.