Greetings my friend, each of the expressions has a peculiar meaning, according to my point of view.
Photo n°1 shows a person who is concentrated and confident, who went out to do a routine on a bicycle, photo #2 shows someone who is fully enjoying the ride and perhaps listens to music appropriate to their tastes, photo 3 shows a person with character who may not like riding a bicycle and who feels a little uncomfortable about it, maybe his weight or height. photo n°4 shows an older person concentrated on the road, worried about not falling and reaching his destination safely. Good exercise yours to do this social exercise, I like what you do.