I am sorry, I have posted on this issue in another thread before spotting this one.
And alas here I found what I was fearing... wallpaper changer gone from WB7, without even Stardock telling you the news.
I can understand that wallpaper changing was not the core business of WB, but at least you should inform people when removing some functionality from an upgrade.
All in all, knowing this I would at least have considered keeping my trusted WB6.4 until this was reintroduced (Neil talks about WB7.1, but it seems far from sure).
Of course there are plenty alternative apps that do this job, even freeware ones, but the point was exactly to avoid any uncessary cluttering of programs in memory.
Thanks for the attention,