Well actually images do belong to there respectful owner. Its not ripping persay to take a picture of an anime charatcer drawn by the artist of the show, but it isn't really legal, its the same as me taking drawn chartcers from Cuc without asking and puttign thme on sigs, just this time its not a major anime selling company its just some guy.
II'd assume takign images from a ocmpany is the same as tkaing images from someone who drew them. For instance. If you drew Goku lets say and someone used him in a sig. Its the same thing as if your an artist in a nation wide anime company thing as if your a solo artist.
I'm not sure about the laws about taking images from national ocmpanies, but I'd assume its still in ownership of its rightful owner and that useing it is illegal, but nobody has itme to sew or email every person who uses an image of goku or whatever.