User blog comment:Luffy36542/SAO(Sword Art Online) Best show ever/@comment-1173941-20131212013042/@comment-6697950-20131212113146

The .png-only rule only applies to images that are to be used on articles. For personal use-only images, it's your call what format you want to use.

But either way, I vote for deleting them as they are not his original work, yet he's claiming credit for it.