See how the post in the middle looks a bit... odd? There's more of the hedge than the horse on display!
The advertiser needs to review how their advert looks now that they have placed it, check the pictures in the full advert and consider making another the main one to better fit the space they are allocated. With a bit of trimming, I think this one would be much more suitable:
And just for your information, here's the full shot of the other one- you can see where the problem is in terms of how central the horse is (or isn't!) to the image.