Leadimage

I run a small dog related blog – http://www.dogs-worldwide.com. and use the BranfordMagazine Theme.

I use the same image in my lead post all the time. Is there a way I can set that image to appear automatically each time I post or do I have to manually add the image each time I make a post in that category or will I just have to continue setting it manually in custom fields?

Many thanks for any advice offered