1. Do know what stock images have already been used on covers, and try not to use them. Look through other book covers, especially of those in your genre to see what images have already been used and how they’ve been used. Scan through books on Goodreads and Amazon, and be especially aware of images that have been used more than once already. Check out this Goodreads list to help: https://www.goodreads.com/list/show/5051.Cover_Couples?page=1
2. Just because a book is popular does not mean you can ignore rule #1. After Samantha Young hit it big with Penguin, the cover to “On Dublin Street” was being copied over and over again (granted there are many books out there published with this image before On Dublin Street came out, but I noticed a boom in the use of this image after it was released), and it was obvious that authors were trying to cash in on the popularity of that image. But, people will know the difference between your book and the best seller you’re trying to replicate. You don’t want to trick people into buying your book.
3. Stay away from images that are already specific to a certain genre. For example, don't go on a stock photo site and search for an image for your new vampire novel with the search term "vampire". The images you'll find will already be specific to that genre of book making it more likely that someone will recognize it (if the image is used again) because it will most likely be used again in the same genre.
4. Do try and change the image you choose in a way that makes it new and original. Copies are going to happen, especially with millions of books being published every year. The more you can do to change elements of your cover the less likely it will be compared to another book.
These two novels use the same image, but each has a completely different feel.
These two could easily be confused for the same book
5. Don’t be upset if someone uses the same image as you later on. While it may make you feel a little less special it doesn’t mean people are going to stop buying your book. Look at Jennifer Armentrout’s Lux series and Shelly Crane’s significance series. Both feature cover art of the same couple (as a number of other books have as well), both have been fairly popular series’ and neither one has really caused any problems for the other.
