The numbers
| Image | Printed size | Pixels at 300 DPI |
|---|---|---|
| Full page, 6 × 9 in, with bleed | 6.125 × 9.25 in | 1,838 × 2,775 |
| Full page, 8.5 × 8.5 in, with bleed | 8.625 × 8.75 in | 2,588 × 2,625 |
| Full page, 8.5 × 11 in, with bleed | 8.625 × 11.25 in | 2,588 × 3,375 |
| Full-wrap cover, 6 × 9 in, 200 pages, white paper | 12.7 × 9.25 in | 3,811 × 2,775 |
| Kindle eBook cover (front only) | not printed | 1,600 × 2,560 (ideal) |
DPI depends on the printed size
An image has a fixed number of pixels; its DPI is those pixels divided by the inches it covers on paper. A 1,200-pixel-wide image is 300 DPI when printed 4 in wide, and only 150 DPI when stretched to 8 in. The DPI value stored in the file's metadata doesn't change that.
Enlarging a small image adds pixels but not detail, so it can pass a DPI check and still print soft. Start from an image with enough pixels for its printed size, or use an upscaler that rebuilds detail and check the result at 100% zoom.
Kindle images
eBooks are measured in pixels. KDP recommends fixed-layout images of at least 300 ppi (pixels per inch) and a cover of ideally 1,600 × 2,560 pixels; see Kindle cover.
Example: an AI illustration in a picture book
A 1,024 × 1,024-pixel illustration placed as a full page in a picture book at 8.5 × 8.5 in with bleed (8.625 in wide) prints at about 119 DPI, well under 300. The page needs 2,588 × 2,625 pixels: about 2.5 times more in each direction.
Common mistakes
- Checking the DPI number in the file's metadata instead of pixels divided by printed inches.
- Upscaling a small image and calling it 300 DPI without checking the detail.
- Exporting the PDF with a small-file preset that downsamples images below 300 DPI.
- Using 72 ppi web images or screenshots in a print interior.
- Going far above 600 DPI, which makes files heavy without printing any sharper.
In kdpbook: kdpbook's preflight flags images that print under 300 DPI, in the interior and on the cover.