1) I don’t see problem with the logo on your site. Provide us with link to page where you have the issue with the logo.
2) Could you provide screenshot of the issue. I have checked your Media library and all the images are there http://prntscr.com/shm6rl and during header editing also everything is fine https://gyazo.com/03ae6a6a88843716371ae5c7b5be11d4
