Last reviewed by Robert Prime — May 2026
Quick Answer: Each embedded image should be no larger than necessary for its print dimensions at 300 DPI. Oversized images bloat your file past the 650MB KDP cap and slow upload/processing. Resize images to their actual display dimensions before embedding.
Full reasoning, why-it-happens, and the exact fix below.
UK note: UK-specific considerations apply — ISBN purchases go through Nielsen (not Bowker), VAT rules differ from the US (print books are zero-rated; ebooks carry 20% VAT), and GDPR applies to any email/customer data. See our UK self-publishing guides for specifics.
We see this come through our formatting queue at publishing.co.uk regularly, so the patterns and fixes here are based on what actually works at upload.
What this error means
Even when total file size is under 650MB, KDP can reject individual images that are unreasonably large. The two main triggers:
For EPUB: any single image over roughly 5MB can be flagged. KDP's Kindle store optimises image delivery; oversized embedded images bloat delivery fees and can crash older Kindle hardware. The rejection email reads "One or more images in your file are too large to display correctly."
For PDF: images embedded at very high DPI (600+, when 300 is the print spec) waste file size and processing time. KDP flags PDF interiors where individual image objects exceed reasonable size for their print dimensions.
This rule overlaps with the total file size rule but fires earlier — you can have one rogue image at 25MB and the rest of the file is fine, yet the upload still rejects.
📎 Source: KDP's authoritative documentation on this rule is at KDP's file-size specifications.
Why it happens
Photoshop "Save for Print" at 600 DPI. A full-page 8.5×11 image at 600 DPI is 5100×6600 px — 30MB+ uncompressed TIFF, 8–12MB JPEG at max quality.
Embedding RAW or layered PSDs as illustrations instead of flattened JPEGs.
Vector EPS files that contain raster previews — the preview can be massive.
Children's book illustrations done in Procreate at 4000×6000 px and not downsized before EPUB export.
Cookbook food photography at maximum camera resolution (24MP) without downsizing.
Screen captures from 4K displays — single screenshots can be 12MB PNG.
The fix
Step 1: Identify the oversized images.
For PDF: Acrobat → Tools → Optimise PDF → Audit Space Usage → image-by-image breakdown.
For EPUB: open in Sigil → File Inspector → sort by file size.
Step 2: Decide target dimensions and quality.
- Print PDF: 300 DPI JPEG Quality 9 at the size the image actually prints
- EPUB body image: 1500–2000 px on longest edge, JPEG Quality 80
- EPUB cover: 1600 × 2560 px (the KDP recommendation)
Step 3 (Photoshop, per image):
- Open the source
- Image → Image Size → set to target dimensions, resolution 300 PPI (print) or 72 PPI (EPUB)
- File → Export → Export As → JPEG → Quality 80% (EPUB) or 90% (print) → sRGB (EPUB) or CMYK (print)
Step 4 (Affinity Photo, per image):
- Document → Resize Document → target dimensions
- Export → JPEG → Quality 85
Step 5 (free tools): For batch compression, use Squoosh (squoosh.app, free) or ImageOptim (Mac). Drag every image in, set MozJPEG quality to 80, download.
Step 6 (PDF): Re-place compressed images in your source document. Re-export the PDF.
Step 7 (EPUB): In Sigil, right-click each oversized image → "Replace" → choose the smaller version. Save. The reference in the OPF stays the same so no manifest editing needed.
Step 8: Verify. Open the compressed images at 100% — they should still look sharp at the size they display in the book. If they look soft, increase JPEG quality and retry.
Step 9: Re-upload. KDP's preview will confirm images render correctly on every Kindle device.
How to pre-flight it
Our free KDP Readiness Score lists every embedded image with its file size DPI. Oversized images are flagged red with replacement suggestions. Plus 30+ other KDP rules in one pass.
Related errors
- KDP error: file size over 650MB
- KDP error: low-resolution interior images
- KDP error: RGB instead of CMYK
FAQ
What's the maximum size for a single image? KDP doesn't publish a hard per-image cap, but anything over 5MB in EPUB or with very high DPI in PDF can be flagged. Aim for under 2MB per image to be safe.
Will compression hurt my cookbook photography? JPEG Quality 80 with proper sizing is the industry standard for photo cookbooks. You won't see degradation at normal viewing distance.
Can I use PNG instead of JPEG? For photos, no — PNG is huge for photographic content. For diagrams, logos, line art, PNG is fine and often smaller than JPEG.
Are vector images counted against this limit? Vector data (SVG inside EPUB, vector content inside PDF) is small and not normally a problem. The limit affects raster (photo / illustration) data.
Frequently asked questions
How do I shrink images without losing quality?
Use ImageOptim (Mac), TinyPNG (web), or Acrobat's Optimize PDF tool with the 'Reduce file size' preset. Target 300 DPI at the actual print size, not the original photo dimensions.
How do I find which images are bloating my PDF file size?
Open the PDF in Adobe Acrobat → Tools → Optimize PDF → Audit space usage. It shows the byte contribution of every image in the file. Usually the culprit is 2-3 oversized hero images that can be down-sampled without visible loss.
Will publishing.co.uk down-sample my images for me?
Yes — we down-sample print images to 300 DPI at output size (typically a 50-70% reduction in file size without any visible quality loss). Web-bound images go further. The goal is to keep the file under KDP's 650 MB limit while preserving print sharpness.
Why does file size matter if KDP technically supports up to 650 MB?
Files over ~100 MB upload slowly, fail more often on weak connections, and take longer to render in KDP's previewer. Authors who upload near the cap often get a vague "upload failed" error and waste a day re-trying — under 50 MB is the practical sweet spot.
Related KDP error fixes
If you got the rejection above, you may also want to check these related issues — they tend to cluster:
Full list: KDP formatting errors hub · KDP rejection fixes hub · KDP rejected my book
About this guide
This page is part of a series of UK-focused KDP rejection guides at publishing.co.uk, each documenting a specific reason KDP can reject a print or Kindle file and the exact fix. Written by Robert Prime — founder of publishing.co.uk, co-runs the LoveReading network, and has overseen 500+ KDP submissions through formatting work in this category (images).
If you'd rather have someone else handle this and the other 35 issues KDP checks for, our formatting service is from £69 with a 3-day turnaround and a 100% KDP-acceptance guarantee.
Run a free KDP Readiness Score on your file before you upload — catches this issue and 35 others, in 60 seconds.
