Sorry for late response. I live where we were hit by the blizzard and also more ice/snow several days later. Power outages, etc.
I should have been more specific in my question, but the animated wallpapers I am referring to are Opera's own. And yes, they keep disappearing regardless of what I disable. This week one lasted for two whole days and I thought the problem was fixed but when I opened a new tab it was back to those colored, geometric shaped "default wallpapers" for want of better words. I had added nothing new by way of extensions, downloads from the Internet etc. This did not occur right after Opera's latest update (I have the latest version and am running Win 7 sp1) , but it began many days later so it had nothing to do with the update as far as I can tell.
Looking over these forums I haven't been able to find anyone else with the same problem. It is very frustrating as there are some beautiful wallpapers that Opera offers. It's not the end of the world of course, but the suddenness of the problem is something I do not understand Also it is unpredictable and seems to follow no pattern (i.e., after rebooting, shutting down etc.)
Thanks to both of you for replying. If no solution I guess I'll just have to learn to live with it. None of the wallpapers I have downloaded install themselves permanently. Each time I have to go back to the "install" button on the wallpaper itself. There are about five that still remain as installed but anything shortly after Christmas does not show up in the settings category.
Thanks and have a pleasant day.