If you’re serious about designing your own book covers, you’ll need to familiarize yourself with graphics and images. Thanks to several online resources, you don’t have to be a photographer or graphic designer to add professional images to your book covers. Royalty-free graphics are copyrighted images that can be purchased and downloaded for one-time uses. Because book covers are considered a one-time use when used for a single title (usually up to half a million copies sold), royalty-free graphics are a popular option.
Price
Small and stand-alone graphics that will work on book covers run as low as $8, while full sized backgrounds can be as much as $15-$30. Any more than that won’t get you a better cover and will quickly bite into your design budget. You don’t need to pay a lot to create and design outstanding book covers, so keep your spending low.
Size / Resolution for Book Covers
Royalty-free images are available in a variety of sizes, measured in pixels. The higher the pixel count, the higher the resolution. Multiply the desired length of each edge (in inches) by 300 to determine optimal pixel size. For example, a 6×9 full-size background image should be at least 1800 (6 x 300) by 2700 (9 x 300) pixels. On the other hand, a 2-inch square stand-alone image can be as small as 600 by 600 (2 x 300). An image can be reduced from its maximum dimensions without losing quality. However, if expanded beyond its maximum size, it will become pixilated and blurry.
Finding Images for Book Covers
The most popular royalty-free websites allow users to enter key words that generate hundreds of images, many I though not most) of which are quite suitable for book covers. For more efficient searches, take advantage of the advanced search options to narrow your results. You can usually sharpen your search by specifying landscape vs. portrait, photo vs. illustration, etc. If you need an image with room for text, type the word copy or copy space after your entry. Be prepared to spend a lot of time finding images that are not only appropriate, but that will truly work for book covers.
Purchasing Images
While some companies sell images for a set price, many insist on a system of credits rather than dollar amounts. You must first buy credits and then use them to purchase and download images. Packages and subscriptions are also available.
Royalty-Free Sources of Images for Book Covers
The past decade has seen an explosion of companies offering royalty-free photographs and artwork. To ensure high-resolution / high-quality images, stick to well-known companies, including those listed here. 
Istockphoto.com Bigstockphoto.com
Fotolia.com Depositphotos.com
Dreamstime.com Shotstop.com
123rf.com Shutterstock.com
Photos.com sxc.hu
EroticaStock.com and HotDamnStock.com for romance and erotica covers.
Free Graphics for Book Covers
While the majority of free graphics available on the web are low-resolution images not suitable for book covers, a few exceptions exist. An unexpected, but outstanding source is at http://office.microsoft.com/en-us/images (type Microsoft images into Google). This is one of my favorite places to find cover art, and surprisingly few people know about it. Not only do they have a huge selection, searchable by keywords or categories, they have photography as well as illustrations.
That’s all on buying graphics for book covers. Thanks for reading!
Next: Small Images, Color Blocks and Lines
Previous: Graphics and Images Part 2: Layout
By Stacie Vander Pol