Whenever I see a blog with fanart, I always look in the description for source and credit to the original artist. "Credit to original artist" or "I found it on google" is not a proper source. You have to actually write the artist's name in the description. It bugs me because I see so many blogs with minecraft fanart, and there's no source. Not to mention many artists prefer their art not to be reposted without credit. Whenever you use fanart for a picture, PLEASE take time to find a source. It's extremely disrespectful not to credit an artist  for their work.