Now..on the other hand..those that steal pics to warp them or make fun of someone....then yeah. Thats pretty sick behavior because it IS for nefarious reasons.
I don't use my real pic as an avie because some people like to do exactly that. Or use my pic as some kind of weapon against me. "Yer ugly" or "what a fatso" or "you look older than you claim", etc etc etc.
My avies I use are for how I feel. My emotions. Or my mood. Pics I do post I am careful about because I don't want what is dear to me (family, friends, pets) to be used in a negative way. So I post mundane things..like flowers I see, landscapes, etc.
Even in PM, it's a risk here. Was in a multi pm with a couple of people and we felt safe enough to share pics of ourselves with each other until one decided to blather on about how fat another person was. Crude, cruel, and childish behavior but it was a lesson learned.