Connotation is, in a nutshell, a poetic way to express something. So, when you look at an image, or when you read a text, you have two ways to understand them. You can analyze exactly how it's presented to you (in this case there's the use of logical elements), or you can interpret using your feelings. What do you feel when you looked at the image or read the text? That's why this scene evokes serenity and warmth because is the photography of a nature sight.
A microscope is a measuring device. Least count and small count are not scale divisions they are not accurate which only leaves you with millimeter which is an actual scale division.