KDP error: images below 300 DPI

This rejection confuses everyone, because the image file probably says “300 DPI” right in its properties. KDP isn't reading that label. It's doing arithmetic — and once you see the arithmetic, you'll be able to check every image in your book yourself.

What KDP is actually saying

DPI means dots per inch: how many pixels of your image land in each printed inch. KDP requires at least 300 DPI at the printed size. The formula is:

Effective DPI = image width in pixels ÷ printed width in inches

Work one example and it clicks forever. Say your image is 1,200 pixels wide:

• Printed 4 inches wide: 1200 ÷ 4 = 300 DPI — passes, exactly.
• Printed 6 inches wide: 1200 ÷ 6 = 200 DPI — flagged.
• Printed full-page at 8.5 inches wide: 1200 ÷ 8.5 = 141 DPI — flagged, and it would look soft on paper too.

Same file, three verdicts. That's why the “DPI” number stored inside the file (often 72 or 96 on anything that came from the web) is just a label — it changes nothing. What matters is pixels divided by printed size. The reverse of the formula is just as useful: pixels you need = printed inches × 300. A full 8.5×11″ page needs an image at least 2550 × 3300 pixels. A 6×9″ cover front needs at least 1800 × 2700 pixels — before bleed.

One extra note for line art: black-and-white line drawings (coloring pages, diagrams) are made of hard edges, so they show low resolution sooner than photos do. 300 DPI is the floor; crisp line art is usually produced at 600 DPI, and it visibly prints cleaner.

Check it yourself

1. Get the pixel size of the image file: right-click > Properties (Windows) or Get Info (Mac), or open it in any image editor.
2. Decide how wide it prints in your book — half page, full page, a small spot illustration.
3. Divide pixels by inches. 300 or above: fine. 200–300: it'll likely be flagged, or pass and print soft. Below 200: replace it.
4. Repeat for the cover at full size — covers are the most common place this error hides, because they're the biggest printed area in the book.

How to fix it

Go back to the source

The only real fix is more pixels. Re-export the image from wherever it was made at a higher resolution, or re-scan physical art and photos at 600 DPI so you have room to crop. If an illustrator or stock site supplied the art, download the largest version they offer — not the preview.

Replace the web copy with the original

Images that passed through Facebook, WhatsApp, or a messaging app have been quietly shrunk — sometimes to a quarter of their pixels. Find the same image in your camera roll, cloud storage, or email and use that one instead. This one swap rescues more books than everything else on this page combined.

Print it smaller

Resolution is relative to size, so the layout itself is a fix: the same 1,200-pixel image that fails at 8.5 inches passes at 4. If the image matters but the pixels don't exist, give it a smaller home on the page.

On the cover

Build or export the cover art at 300 DPI at full wraparound size from the start — back cover + spine + front cover + bleed. Scaling a small image up to cover size at the end is how this error gets in.

The honest limit

Upscaling can't rescue an image — it can only disguise the numbers. Software (including AI upscalers) raises the pixel count by inventing plausible detail. KDP's checker may then pass the file, but a blurry photo stays blurry on paper; faces, fur, and any text inside the image suffer most, and your readers hold the proof in their hands. If the picture matters, hunt down the original file. This is the one error in these guides that no PDF trick can truly fix — we'd rather tell you that here than have you learn it from a printed proof.

More KDP rejection guides

• Spine text error — too close to the spine edge
• Bleed error — “your file does not include bleed”
• Margin error — text outside the margins
• Page size does not match the trim size
• Fonts are not embedded
• The free KDP rejection check — all 13 checks at once