What is changing Pixels Per Unit doing exactly?

[MyTHos]

Here, when we add the Germ_2 sprite and ‘shrink’ it by changing PPU,
Are we actually resizing the image (reducing number of pixels)
Or is the sprite in the game still the same resolution (same number of pixels) being displayed differently?

Thank you.

[bixarrio]

Perhaps this article could shed some light
Calculating the Pixels Per Unit (PPU) for a Background in Unity | by Chris Hilton | Medium).