To print book covers, first determine the size of your book, considering that the largest size in which glossy card stock at copy stores comes is 11-by-17 inches or 12-by-18 inches. Books sized at 5.5-by-8.5 inches or 6-by-9 inches allow for enough printing room, plus bleed space. Use these measurements to create a layout in a photo editing program, such as Adobe Photoshop. Once the design is complete, print it onto the appropriate stock paper, and have it professionally bound.
The total measurement of the cover, spine and back cover equals about 9 by 12 inches for either of the recommended book sizes. Leave about 1/8-inch bleed space on the edge of the cover space to ensure that there is not a blank or white border on the outside edge of the book. Mark this space in the photo editing program with the page setup to contain the cover design inside of that margin. Insert photos, images and text boxes to design the cover, and choose a stock paper color if you want to choose something other than the standard white cover. Print a test page to check that the cover is as desired.
Consider having the actual printing done professionally to achieve a high-quality print and color saturation. If printing on your own, ensure that the design prints on the glossy side of a glossy stock paper. It is also recommended to hire a professional book binder. If not, use a paper clip to score the cover for the spin folds, and glue the cover using a polyurethane reactive glue onto the bound pages of the book. Check all measurements beforehand to ensure the cover is the right size, while also keeping it as straight and even as possible.