Here are the latest news about the backgrounds appearing too small:
The good news first. I fixed all the background codes, so they should work just fine. (but if there is still problems with any codes, please leave a comment and I will fix the problem).
And then the bad news. You have to replace your existing background code with a new fixed one of your own. You have to find the HTML/Java Script gadget where you have the background code and remove the old code and then add the new fixed code.