The title says it all, doesn't it, more especially when you're an Indie author. Stock photos with models in fancy dress are easy to obtain, and what else is there in avoidance of breaching copyright artwork?
Stock photos rarely cut the mustard for many historical novels when the hero is wearing the wrong uniform (something out of Disney fairy tale), wrong shirt, and modern riding boots. Yep, those boots and open shirts are the big fail. Men didn't wear button-through shirts they wore smock shirts What is more, a beautiful 21st century evening gown with deep cut back and falling off the heroine's shoulders kills the sense of true history for die-hard fans of specific historical periods, as do strapless gowns. And the worst case scenario is when you've penned a Regency and your hero and heroine are on your cover in all their finery and perhaps indulging a provocative pose, and then, Oh No, you see the same cover on a Victorian novel, as do readers who then wonder if they have the right book because they purchased a novel a few days ago sporting the same cover. And sometimes there's worse to come when you see the title is the same as on your book, and hopefully set in a differing period or another era. The Reformed Rake is a popular one, or To Wed a Duke, et al. You know the trending as well as I do.
So what to do, if you are as period specific as I am, in not only using archaic prose, but seeking that image you have in mind that depicts a special scene or moment from your book? Yep, it's pretty much an impossible task unless you are moderately handy with pencil and paints, being water colour, acrylics, or oils. So what else can you do?
A lot of authors look around for a lovely portrait of a man or woman from the chosen period in which their novels are set, but there can be a bit of catch in that with breach of use, because some of the most famous portraits are of famous people, So how can you possibly have Lady Grantham as your heroine, who is, for fiction's sake, Lady Annabelle Marchment? This portrait may indeed belong to the Grantham's and may not truly be in the public domain, it being a private family portrait. To say the artist is long dead therefore his original artwork is all now public domain, unfortunately family portraits were commissioned for private display and inheritance, And unless those portraits have been sold on the open market and are public domain for open commercial licence usage as reprints, and note a book cover is a reprint for commercial use, then be wary for you could find yourself in court for profiting from private property!
Just because some happy snappy tourist sneaked out a camera or pointed their smartphone at a portrait whilst tramping around an English Stately Home, and then posts the happy snaps on their Pinterest page, that doesn't give carte blanche to use those pics as a commercial item.
But you can indeed seek out public domain artwork by famous artists, but always check to see if they are free of restrictive licence. If you want a classical image to represent your hero or heroine there are many, many unnamed miniatures in the public domain, some enchantingly pretty ladies, and others less fortunate but may be perfect for that ugly duckling romance story!
I used this one for Adelle la Comtesse Montacute, in The Trevellians' of New-Lyn, She was as I visualised her, and I had her to hand... But -
Take National galleries et al who sometimes charge a fee for commercial usage. And why shouldn't they, for they are what they are National Treasure Houses, where beautiful artwork receives TLC, and where restoration of old paintings, (some disgustingly filthy) which require painstaking concentration and skilled expertise to bring the glory of the original back to semblance of its former self, So do think before you gripe when asking to use artwork for a non-fiction work and you are asked to contribute to the upkeep of the gallery by paying a fee to profit from work that has at best been cleaned if not fully restored, and thank your lucky stars the gallery could provide the work you wanted.
Even though I have for many years created artwork from scratch (pure imagination and by study of other artwork) there are times I have come across public domain artwork that was out of copyright, and I've thought lordy, why did the artist paint her that way, especially ladies on horseback riding side saddle, or I see the horse is out of proportion head wise to it's body. Stubbs is oft a prime example of long backed, sometimes oversized bodies, with fine boned legs and small Arab/Turkman heads. So if horses did indeed look like that back then, all I can say, is that equine wouldn't have given some of the large men standing alongside many years of service. But aside from horses, here's an example of an original Heywood Hardy, and below is my version in which the lady is displayed to full advantage with riding habit flowing. And yes, the image is a reverse image, and the horses and the riders are almost identical but not quite, because I painted my couple with similar hats but differing outfits and distinct faces, unlike the original.
Heywood Hardy - a pretty country scene and as seen on lots of book covers.
My version is depicted with the house the heroine inherits.
And all that said, I quite like elegant still-life classic looking book covers that quite a good many authors turn to for exclusive covers, but you know, with a little imagination one can make a cover from period fashion plates: