"So why do you crop the heads off your models?"
If you look through the romance genres on Amazon, you've probably noticed tons of covers with models positioned so their heads are cropped off by the edge of the book, or turned away from the viewer. What's up with that?
Some cover designers do it to allow the reader to imagine themselves when the model is the same gender, or to allow them to imagine their ideal partner's features in the protagonist of the book.
I do it for a practical reason: there's a small pool of stock photos suitable for romance covers out there, especially when you get to more specialized genres such as Regency romance, and I want someone shopping for a book to focus on the title and design, and not be distracted by thinking about how the griffin shifter dude was a vampire yesterday and a hockey player the week before. Of course, if an author prefers visible heads, I design the cover that way.
I've been doing this long enough that I'm starting to recognize models when when they don't have visible heads! In fact, the model on the cover of Firefighter Griffin gets around quite a lot...