Untitled Film Still #21 is a black and white photograph taken by Cindy Sherman in 1978.

[3] Nicholas Mirzoeff used this image in a chapter of his work "How to See the World",[4] explicitly discussing the way of self-expression from self-portrait to selfie.

For Mirzoeff, the woman in the photo stares in an invisible direction, and the feeling of opening her lips creates a "sense of threat and anxiety".

He pointed out that in the classic Hollywood screen setting, "victims are always isolated like this before they suffer violence."

Untitled Film Still #21 is one of her acclaimed early photos, and the style and architectural style of the costume (more "brighter" than the viewer originally saw it in 1978) is an integral part of its lasting appeal as a single photo.