Name of a specific visual effect

Solution 1:

This is called the Droste effect (Droste effect).

The Droste effect (Dutch pronunciation: [ˈdrɔstə]), known in art as an example of mise en abyme, is the effect of a picture recursively appearing within itself, in a place where a similar picture would realistically be expected to appear, creating a loop which theoretically could go on forever, but realistically only goes on as far as the image's quality allows.

(From Wikipedia)

Solution 2:

'Mise en abyme'. According to lexico.com:

(A term denoting) self-reflection within the structure of a literary work; a work employing self-reflection.

It's also known as 'Droste effect', a "recursive visual effect".
The Dutch Droste company used to have labels on their products that showed a woman carrying a tray on which the same product was placed, with the same woman carrying a tray with.. you get the picture: