Common courtesy is a dying art.
^ See that's just plain wrong. I don't think I have ever said something was mine when it wasn't. At least knowingly.
But I have posted stuff I've modified, and had the wallpaper so long and changed the name from (example)
wallpaper_of_dog_running_up_a_hill_by_standupguy-37655288565-a.png
to:
dog-3.png
then I tweak it and post it ...
I really MUST archive my wallpapers and start over. I have 2384 of them, at one a day I'd need 6.53 years to show them.