If this is the Russians (unproven speculation on your part), it does not mean the emails are not authentic.
If this is the Russians (unproven speculation on your part), it does not mean the emails are not authentic.
The fact that this hasn't been done is concerning, unless it's being sat on for future impact.. the "drip drip drip" method of political bombshell news isn't a new tactic. If we're still here in a week with nothing other than screenshots, we can probably write the messages off as frauds. I'm withholding my judgement for a few days.
The "drip drip" is an intentional strategy, of course. This smells like a setup to me. They leak the lukewarm email, get a denial from Biden, then leak a smoking gun that cannot be denied (speculation).
Really though, even if DKIM wasn't a thing, there's little-to-no reason to only post screenshots if the actual raw files are available.