Blog – show image at top of post – not featured image

Hi;

One of my marketing folk asked if there was a way to format a blog so that we have a standard image (common to all blog posts) at the top when viewing the individual entry. The featured image varies with the post and we like that, especially when looking at a listing of blog posts. We don’t want to replace the featured image, just us a common one in the header for all blogs. Is there a way to make that change? if so, what is it?

Bob