The purity and innocence of a thought captured through color and symbols.
The transformational symbolism of a butterfly which can be found in pure thoughts and the symbolism of dragonflies which as creatures of the wind, the dragonlfy represents change. It's iridescent wings are incredibly sensitive to the slightest breeze, and so we are reminded to heed where the proverbial wind blows - lest we run into stormy weather.
Dragonflies are also creatures of the water, and any creature whose habitat is in, or around water carries symbolism relative the the subconscious, or "dreaming" mind and thoughts.
This is because in the animal world, water is symbolic of the subconscious mind ("deeper mind," "dreaming mind") and relates to the thoughts we have in relaxed/meditative/sleeping/subconscious states. "Pure" thougths.