Some speculate that microsaccades actually increase resolution and perceivable detail in static scenes by basically offsetting the retina a tiny bit. The concept definitely works and is used in practice to boost the resolution of digital image sensors ("superresolution").
It is not but you'll see different image depending on your eyes position when looking at higher resolution image. Think of it as 8k image resampled to 4k but at different offsets. You'll effectively see more detail when moving your head than looking at 4k image.
Why downvotes? It is essentially the same thing when you can read plates from a low resolution movie where on a single frame you can see indecipherable number of pixels but if you combine the pixels from multiple frames and recover the car's offset you can compose higher resolution picture of the plates effectively being able to read them.