In early January, Facebook rolled out updates to cover photos, ads and images. No, they didn’t change the sizes of them again. Instead, they have implemented a Facebook 20 percent rule. What the Facebook 20 percent rule aims to do is control how much text you use on your Timeline cover photo, ads, and in images you want to promote. Before you start to panic though, remember, the Facebook 20 percent rule is there to help you…become a better marketer for your business on Facebook.