Environmental SEMs do not require vacuum and can be used for nonconductive samples. The beam ionizes the air which prevents the sample from charging. Magnification is limited but it is more than enough for this.

You can tell it is SEM and not optical by the depth of field. An optical image at this magnification would have much less DoF so the peaks/valleys would be blurry.

Put a needle in someone, freeze them solid with liquid nitrogen, then take a picture. Throw body out with rest of specimens.

Easy peasy.

It likely wasn't done on an electron microscope, or at least there is no reason to. There is no scale bar, but quick look online tells me a very fine needle is about 0.016in. 500x magnification optical lens would give you more than enough resolution for a photo like that.

I'm more intrigued by the fact there's no blood, they must've taken this milliseconds after the needle was removed? Or it's a dead body.

Probably just a chunk of skin, not a whole person

They could have remained a portion of the skin. But as another commenter notes, this is too large to need an electron microscope.

Edit: then another comment says otherwise, and cites the collection it is from.