With reference to the talksurf header;
I can see where the background image originates, but not the ‘talksurf’ image on the left, which is floating above the background image.
Adding ‘talksurf’ as a image in Settings>Branding>logo results in a much smaller image as Discourse shrinks it from 120px original height to just 31px. Talksurf is a lot more than 31px high