Listen to the Friz, man.
I know sometimes you find things floating around the internet that you think are amazing and you just want to share them, but you need to remember that behind every piece of artwork there is an artist that deserves credit. Even if you aren’t claiming the piece as your own, without a source, the artist who deserves the praise and credit for the artwork isn’t getting it!
Just please please PLEASE, if you want to share a cool piece of art or a nice photograph, FIND THE SOURCE!! Search the tags on tumblr, google it, ask around, do whatever you have to do. Sometimes you’ll be surprised how fast you can find what you’re looking for, and then the artist (or the artist’s disgruntled friends) won’t have to chew your ass over it!
If you find that the artist has already posted the picture on their blog, do them a favor and reblog it from them rather than re-posting it yourself. This way the artist will know when their picture is getting attention. Even if you have already posted it and later find that the artist has it on their blog, go ahead and take yours down and reblog theirs! It’s not very difficult.
And then there’s the sum of you out there who intentionally save pictures and repost them so you’ll get the attention and all I can say to you is you’re disgusting and people like you deserve to be looked down upon.
Find more information about sourcing and why it’s important here.
Also try Search by Image if you don’t have any leads besides the picture itself!