An important thing to know about writing. You have to plant an image of your characters’ looks in your reader’s mind without being obvious about doing so. This is especially hard for the character whose perspective you’re narrating from, even in the limited third-person. The ‘protagonist looks at themselves in a mirror and describes how they look’ scene is a huge cliche, especially when they’re downplaying their looks. So you have to seamlessly find a way to convey this information without seeming to convey it.
However, when you’re describing how you want your book cover to look, you can fuck all that and just send gifs of what their hair looks like.
It’s pretty great. Of course, in the book, poor Mindy has none of the hair and make-up budget that Jane Levy would have in even an indie movie about gay cowboys eating pudding, but I figure Hollywood and romance novel covers operate on the same logic when it comes to looks.