[ETCM]

Off-topic a bit but has any NASA probe sent dark-side pictures of planets and are they dark?

None of the planets emit significant visible light, so the side facing away from the sun is dark. Some do emit infra-red or even x-ray energy that can be imaged.

This image was taken by the Juno spacecraft

[alexander_busek]

Off-topic a bit but has any NASA probe sent dark-side pictures of planets and are they dark?

None of the planets emit significant visible light, so the side facing away from the sun is dark.

Let me expand upon your reply, ETCM:

NO planet or other major celestial body in our Solar System is TIDALLY LOCKED with respect to our Sun.

Hence: No planet or other major celestial body in our Solar System has a permanently dark side.

No real astronomer would ever use the expression "Dark Side." They would, at most, use the expression "Far Side" - though only with respect to our Moon.

It is, of course, to image the (momentarily) night side of a planet or moon. This has been done in the case of, e.g., Jupiter and Pluto.

Result: Mostly black.

Regards,