I guess if I have to explain the joke, I have no one to blame but myself. <sigh>
The redhead in armor is Chappell Roan at this year’s VMAs, and the blonde is Sabrina Carpenter from a performance on SNL. The original photo in the post was making fun of noticing the superficial resemblance of a shot from Buffy the Vampire Slayer to those two looks.
Damn it’s weird being old enough to have been a fan of Buffy, but still knowing and liking new pop music.