A sense of scale: the best microscopy of 2016

The pictures of the dividing cell and the fibroblast are done with a fluorescence microscope, so the colour is a reconstruction of what was there rather than a direct capture. In the case of the fibroblast, it's a rather Warhol-esque reconstruction with false colour; the actin in the picture is white, which it couldn't have been in the microscope. The algae look like natural colour under UV illumination. I'm not sure about the Frontonia; that looks like differential interference contrast, which would mean it has to be natural colour.

The dividing cell is probably on the order of 10 µm across. Light used in microscopy has a wavelength of 400 - 700 nm, and so gives a resolution of roughly 200 - 350 nm. That's enough to see structure in something 30 - 50 times bigger.

As an aside, the pictures dividing cell and the fibroblast both look like they were taken with a confocal microscope - there's not enough out-of-plane light for a widefield microscope. The dividing cell looks like a projection of a quite thick stack of confocal planes, whereas the fibroblast looks like a single plane. That means those images only ever existed in a computer; you couldn't have seen anything like that by looking down an eyepiece.