Source your art. I will not hesitate to flag this blog if you don't start sourcing art. It's plagiarism, and it's illegal. These artists work hard on their art, and deserve credit for it. The rule of re-posting art are clear, 1) get a source, if you don't have a source don't post it. 2) check to make sure that the artist is okay with you posting their work. Make sure they don't have a spot on their website that says not to repost. 3) Link to the source. That's it. It's that simple.
Happy #Otaku Day