Quote from fkapnist on December 24, 2018, 6:59 pm

If you design programs or websites, some objects may render out of place when you preview them. You can do your correction with a guesswork trial-and-error process of compile and run, back and forth, until you finally get it right... Or you can take a screenshot and precisely measure the error.

In this image we see that an object needs to be moved up exactly three pixels.