It’s about an extra $750-1000 to get a really great custom photo for your ad or cover of your book. Is that a lot of money? Of course it is! But, when viewed over the lifetime of the project (the total cost of the ad campaign, the number of books printed, the thousands of brochures handed out), it is pennies extra per ad/brochure/book cover.
Why wouldn’t you spend the extra money to ensure you don’t get caught with someone else’s iconic graphics for your project?