Oswald in the doorway: the blog of the Oswald Innocence Campaign, by Ralph Cinque

It's been pointed out to me that there is a means for claiming copyright using a pseudonym. But, in this case, it's not his pseudonym. It's Homer Simpson's pseudonym. 

In any case, I have properly attributed the source by providing the link to it. Furthermore, when someone puts something in the public domain and it gets reproduced for purposes of criticism, comment, or discussion, it's considered "fair use".  

Mr. Uppercut was not marketing the image; he was inviting and encouraging public consideration of it. And I did nothing to commercialize it, claim it as my own work, nor did I fail to attribute it to him.