Please don't just change your picture because it's the latest internet trend. Solidarity isn't about changing your profile picture. It's too easy to do that. It's about changing your attitude and uniting with everyone. It's deeply screwed up and scary to think that if I changed my profile picture every time there is lives lost at the hands of extremism, I would be changing it every day.
I set up my profile and became one of those quiet weirdos just watching at first. I say weirdos. You're not weird if you watch, but if you're the one talking live on screen, it's pretty unnerving to see you have ten watchers and only one talking to you. It leaves me wondering "who are these people!?"