Hi there! My name is***** am a computer professional with over 15 years of experience with both Mac and Windows computers, phones, tablets, and printers. It would be my pleasure to assist you with this. Can you provide a link to your blog post please? Generally, when you post outside links on Facebook, Facebook pulls the header photo from that website and inserts it. I'll take a look at yours and see what I can tell from a glance. It may be necessary to remotely connect to your computer to work on this as Iwon't be able to make any changes without being logged in.