Shareability · 18 points
twitter:image
One check, stated three ways: what we measure, what would make it wrong, and how to confirm it yourself.
What this measures
Whether a twitter:image property is declared, and whether it resolves to an absolute URL. We do not re-fetch it here — og:image is the one we actually request.
Where this check can be wrong
It is redundant when og:image is set and correct, which is why it is weighted lightly.
Verify it without taking our word for it
Grep the head. If og:image already resolves and you have no specific reason for twitter:image, skipping it is defensible.