I really think you need to change that tagline at the bottom of your wallpapers. Instead of "Images are the property of their respective owners.." it should give a specific credit to whoever (or whatever organization) took that picture.
Of course images are the property of who took them. You need to give credit to that person, not point out the obvious. -- To an extent, simply saying "images are property of respective owners" is insulting.
.. you might as well put "I don't own the rights to this picture, someone else does, but I'm stealing it anyhow."
It's clearly better to credit the photographer .. second best is to remove that line completely, as it doesn't absolve you from infringing on someone's ownership.
