I loved the original cover, the Russian postcard, but I suspect people perceived it as "dated". So then I got the photo of the wild geranium and I loved that but changing was more for me than thinking it would actually improve sales. Why? Because it was too soft.
As I was looking at photos in one of the stock image sites, I happened on a couple vector graphics that I thought could be made to work. I bought one and I've probably put 20 hours in on it to get it right for my purposes. The original had a horrible grey sort of background so I needed to lift the girl off that. Then her skin tone needed to be adjusted, change her hair color and you get the picture. It was very labor intensive.
Now I can go back to my novel.