This post is intended for anyone who likes to make and post things like this:
But this post is especially written for authors who post fellow authors' words. And use them as, say, the cover photo for their author page on Facebook. With no attribution to the author who wrote them. This is mind-blowingly simple: If you don't attribute those words to the author who wrote them, you're being dishonest as a writer at best (to people who might assume that thought/ poem/ bit of dialogue came from your head) and committing copyright infringement at worst (on the author of those words - something you of all people, as a writer, should understand).
No, it isn't enough to put the attribution in the description or the comments. People download photos and share them, separating the photos from your description of them - and yes, photos can be altered to remove words, and there's nothing to be done about that. But at least, for God's sake, give it a shot.
Keeping the attribution with the quote prevents your followers from thinking some awesome sarcastic saying or poem or bit of literary wisdom is something written by you.
Of course - if you don't care about that, and you're an author, I can't help you. If you're okay with posting someone else's words as your Facebook cover photo, with no attribution to that author at all... I guess that tells the world everything it needs to know about you as a writer, huh?