Flies are of the large order Diptera and characterized by sucking mouthparts and a singular pair of transparent wings. They can be minor and major irritants, from buzzing around the trash to affecting entire herds of cattle. Humans have devised numerous ways of diverting and killing flies: screened windows, fly swatters, electric fly swatters, electric outdoor bug zappers, and fly paper strips. Flies are mostly associated with rot and decay, as that is what they are most attracted to, but their early life form—maggots—also have been used in medical treatment for cleaning wounds.
As annoying as flies can be, they are of utter importance and we should respect them more. So start using great photos and make them more visible - or illustrate at least whenever something stinks with images of a fly!