The likely problems are incorrect ordering in HTML files or incorrect ... which create a hard line return after the header and center whatever is in it:display:block; width:100%; text-align ...

The chief reason for using X-Frame-Options is to prevent the use of HTML ... mode=block X-Firefox-Spdy: h2-15 Conversely, with the igu=2 parameter appended, the X-Frame-Options header was omitted ...

even if you upload one to the Header section. You must edit the blog HTML to add your own header image instead.