For paperback production, CreateSpace suggests that all images used for the interior of the book be 300 DPI. Images that are less than 200 DPI will be flagged when submitting the interior during the review process. You can still submit and publish a book with images less than 200dpi but the printed image *may* be slightly pixelated.
DPI stands for Dots per Inch and without getting too technical it is essentially just information to tell the printer how detailed to print within a given inch, so the higher the DPI, the higher the printed quality.
To make sure that your images don’t get flagged during the CreateSpace approval process, you should make sure that each image resolution is set to 200 DPI and above. You may notice that when working with software to change the resolution of an image, it is referred to as PPI (pixels per inch) instead of DPI. In our case even though the terms DPI and PPI have different technical meanings and uses, we will consider them to be the same thing for achieving a high quality printed image.
Software such as Photoshop, Lightroom and a free program called Gimp can be used to manipulate an image’s PPI (resolution).
If all of this seems confusing and you’d like our help with identifying if your images are of high enough quality for printing, just let us know. We can also provide services to convert your images to the proper DPI. We just need to make sure that you provide us with large enough original images.
Below are examples of how the print size changes when you change an image’s resolution. Notice how the pixel dimensions stay the same for viewing the image digitally, but the document size (printed) width and height changes so you will have a much smaller printed image potentially when you upscale the resolution. Click on the images to expand.