To be fair, the images are large because that's what he's selling. Photographers don't have the luxury of reducing the size of the images on their websites too much because if they did, they'd get no work. Also, this isn't his primary business site: it's a sub-site for a particular area in which he works, and the potential clients who are the primary consumers of it aren't starved for bandwidth.
He is, in fact, an expert at reducing image file size for web use without compromising perceived image quality. If I want guidance on that rather recondite area of expertise, he's the person I'll ask.
Compare his site to almost any other photographer who puts images of that perceived quality on their site, and you'll see that his site is literally megabytes smaller than theirs.
But the OP asked for examples of WP themes being used on real business sites, and that's why I linked to it.