Marp,
As an artist, I feel like you should be copyrighting images you create. It was your sweat and blood that create these masterpieces and I believe you should take steps to protect your work. Otherwise any ol' jackass off the internet will be using them. I have a lawyer on retainer (although his specialty is public indecency) and can provide you with his number if you need assistance.
“Art washes away from the soul the dust of everyday life. Cocaine is awesome.”
― Pablo Escobar