Romance covers changed noticeably over the past decade, moving from photographic couples towards flat, brightly coloured illustration. The shift solved several problems at once, none of them about taste.
Covers are now seen at thumbnail size
Most discovery happens on a screen, where a cover appears as a small image in a grid alongside dozens of others.
Photographic scenes lose their detail at that size and reduce to an indistinct mass, while flat illustration with strong shapes and limited colours stays legible.
A cover that reads clearly at thumbnail size gets clicked, and clicks feed the retail systems that decide what gets shown next, so legibility compounds into visibility.
The old covers carried a social cost
Photographic clinch covers announced the genre to anyone within sight, and many readers disliked reading them in public or leaving them visible at home.
Illustrated covers removed that exposure without hiding the book, since they signal romance clearly to people who know the conventions and remain unremarkable to everyone else.
That change matters commercially because a book people are willing to be seen holding is a book that gets recommended in person and photographed online.
Illustration widened the shelf
Photographic covers implied a fairly narrow set of stories. Illustration can carry humour, warmth or lightness, which suits a large part of what the category now publishes.
The style also travels easily across subgenres, letting a publisher signal comedy, small-town warmth or workplace tension through palette and composition alone.
Because the images are drawn rather than photographed, the characters can also be depicted with a range that stock photography did not readily supply.
Production advantages reinforced the trend
Illustration avoids the licensing complications of photographic models, whose images are licensed for limited terms and territories and can appear on competing books.
An illustrated cover can also be adapted for series consistency, translated editions and promotional material without a new shoot or a new licence.
Artwork commissioned once can be recoloured, cropped and rearranged across formats, which makes a coherent series look expensive without repeated production costs.
Every convention eventually saturates
Success produced imitation, and a wall of similar illustrated covers now poses the same problem the photographic style did: nothing stands out.
Packaging conventions move in cycles for this reason, and the current style will be displaced by whichever approach next makes a book distinguishable in a crowded grid.
Some publishers have already begun reintroducing photography and typographic covers for exactly that reason, since being unlike the current default is now the distinguishing move.