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.

It was a complaint about 25 years ago when the first iteration came out. There was a full King of the Hill episode about it. Since then they refined the low flow toilets to be as good as the older style.

https://m.youtube.com/watch?v=J4f0MeoV5pQ&pp=ygUga2luZyBvZiB0aGUgaGlsbCBsb3cgZmxvdyB0b2lsZXQ%3D