Kona...the 'beauty of the wallpaper' is not the user's to distribute, unless it's the user's wall.
Chickie....the concern is that a screenshot is supposedly just that....a desktop in action, and not an unobstructed wall....especially 'if' that wall may be a commercial product, as was the case in a previous instance.....the one that resulted in much furore and dummy-spitting.
The only person 'entitled' to distribute a wallpaper....in any shape or form or by any method or artifice is the creator of that wall, unless express permission is sought and received [and included with the distribution]...