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Authors: Preflight EPUB Cover at 2,560×1,600 px to Avoid Rejections

September 26, 2026
Authors: Preflight EPUB Cover at 2,560×1,600 px to Avoid Rejections

Target 2,560 × 1,600 pixels (1.6:1 ratio) for your master cover file. That satisfies Amazon KDP's ideal spec and gives you room to export smaller versions for Apple Books, Kobo, or Google Play. Never go below 1,000 × 625 px, and if you're building an internal EPUB cover rather than a marketing thumbnail, 1,200 × 1,800 px is a safer bet. The rule that governs everything else: design in pixels first, then worry about DPI.

TL;DR:

  • Creating a master cover at 2,560 × 1,600 pixels in RGB ensures sharpness and flexibility for different retailer specifications without quality loss.
  • Amazon KDP recommends a cover of 2,560 × 1,600 pixels with a minimum of 1,000 × 625 pixels, accepting JPEG or TIFF files and emphasizing pixel count over DPI for clarity.
  • Retailers like Apple, Google, and Kobo have distinct size and aspect ratio requirements, making a large, scalable master file essential for meeting all standards.
  • Exported images must be properly embedded in EPUB files with correct manifest properties and media-type declarations to prevent rendering issues and rejections.
  • Using validation tools before uploading can catch common packaging errors, such as missing properties or resolution problems, ensuring a smooth publication process.
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Table of Contents

The 2,560 × 1,600 px target isn't arbitrary. It's the figure Amazon KDP publishes as its ideal cover size, and because Amazon still drives the largest share of ebook sales for most self-published authors, that spec has become the de facto industry standard even on platforms that never mention it directly. The 1.6:1 ratio behind it also happens to crop cleanly into the thumbnails you see across every major store, so a cover built to this spec rarely looks stretched or oddly framed when it shrinks to icon size on a phone screen.

You'll also run into two other common targets, and each has a specific job:

  • 1,600 × 2,560 px — the same ratio, oriented as width by height. Some workflows and export tools label dimensions this way, so don't panic if you see it flipped.

  • 1,200 × 1,800 px — a 2:3 ratio that's common for internal EPUB cover images (the page a reader sees when they open the book), as opposed to the marketing thumbnail used on a sales page.

  • 1,000 × 625 px — the floor. This is KDP's stated minimum, and going below it risks rejection or a blurry, pixelated result at full-screen size.

Build your master file large and scale down, never the reverse. Upscaling a small image to hit a pixel target introduces visible softness and artifacting that no amount of sharpening filter will fully repair. Downscaling a properly built 2,560 × 1,600 px master, by contrast, loses nothing a reader would notice. If you only ever create one file, make it the big one.

What Amazon, Apple, Google, and Kobo Actually Require

Each retailer publishes its own cover spec, and the differences matter more than most authors assume. Treating one platform's numbers as universal is the fastest way to get a rejection email during upload.

Amazon KDP wants an ideal cover of 2,560 × 1,600 px, with a hard minimum of 1,000 × 625 px and a maximum of 10,000 × 10,000 px. KDP accepts JPEG or TIFF files, applies its own compression on the retail site, and recommends minimal compression on your end plus a 300 PPI setting for quality assurance. That PPI figure is guidance, not a hard gate. Pixel count is what actually determines sharpness.

Apple Books asks for an RGB JPEG or PNG with at least 1,400 pixels on the shorter axis. Apple's asset guide treats 300 dpi as a rule of thumb rather than a technical requirement, but it's stricter about internal EPUB images, capping them at 5.6 million total pixels and recommending art sized at least 1.5 times its intended viewing size.

Google Play Books accepts JPEG, PNG, TIFF, and PDF cover files. Google's own documentation is inconsistent about the minimum, listing 1,024 × 1,024 px in some sections, so use that stricter baseline whenever you're preparing a new file. The partner help center also caps files at 7,200 pixels per side and 2 GB, limits you'll never hit with a properly compressed cover.

Kobo suggests a 3:4 width to height ratio, citing an average store cover of 800 × 1,224 px. Kobo's guidance draws a firm line between the external store cover and the internal EPUB cover, which needs its own standalone XHTML file to display correctly and avoid triggering fixed layout behavior on e-ink devices.

Comparison of four ebook retailer cover requirements

Format, Color Profile, and Compression Settings That Actually Matter

Use JPEG for photographic or painted covers and PNG when your artwork has sharp edges, flat color fields, or needs a transparent background. TIFF works where a retailer specifically allows it, but it produces much larger files with no visible quality gain for a JPEG-appropriate image, so save it for cases where compression is genuinely unwanted.

Export every cover in RGB. CMYK is a print color space, and dropping a CMYK file into an EPUB workflow shifts colors unpredictably across different reading apps and screens. This trips up authors coming from a print-design background more often than any other single mistake.

On DPI: set it somewhere in the 72 to 300 range as retailer guidance asks, but don't lean on it for sharpness. Apple's own documentation frames pixel dimensions as the real driver of clarity on screens, with DPI functioning mostly as metadata. A 2,560 × 1,600 px file at 72 DPI looks identical on a Kindle Fire to the same file at 300 DPI. Only pixel count changes what the reader actually sees.

  • Keep a full-quality master file uncompressed or losslessly saved before you export anything else.
  • Compress only as much as needed to clear a retailer's file-size ceiling.
  • Re-check the exported file at 100% zoom for banding or blotchy artifacts before uploading.

Pro Tip: Export your JPEG at quality 90 or higher first, check file size, and only step down from there if you're still over a retailer's limit. Jumping straight to a heavily compressed export to "save time" is the single most common cause of a pixelated cover that looked fine on your monitor.

How to Embed the Cover Correctly Inside Your EPUB File

A cover that looks perfect as a standalone JPEG can still render wrong once it's inside the EPUB package, and the fix has nothing to do with pixel dimensions. It's a packaging problem.

Start by placing your cover image in a dedicated file, typically images/cover.jpg, and build a standalone XHTML document that contains nothing but that image. Kobo's guidance is explicit that mixing the cover with other page content in the same XHTML file can trigger fixed layout rendering on some e-ink devices, even when the rest of your book is reflowable. Keep that file minimal.

Illustration of EPUB cover packaging components

Next, declare the image in your content.opf manifest with the properties="cover-image" attribute for EPUB 3, and add a corresponding entry in your metadata section. A typical manifest line looks like this:

<item id="cover-img" href="images/cover.jpg" media-type="image/jpeg" properties="cover-image"/>

Older readers and some retailer systems also check for a <meta name="cover" content="cover-img"/> tag, so including both covers your bases across EPUB 2 and 3 compatible systems.

The three failures that break an internal cover almost every time: a missing cover-image property, a mismatched or incorrect media-type string, and an XHTML cover file that got extra elements added during export and now confuses e-reader rendering engines.

Double-check your media-type string matches the actual file format. A PNG declared as image/jpeg will often display as a broken image icon instead of your cover, and that error is invisible until someone actually opens the file on a device.

Your EPUB Cover Sizing Checklist Before You Upload

Run through this sequence every time, even on your tenth book. Skipping a step here is how a fine cover on your desktop becomes a rejected upload or a fuzzy thumbnail on a live product page.

  1. Design your master file at 2,560 × 1,600 px in RGB and save it uncompressed.
  2. Export a retailer-specific marketing thumbnail (matching KDP, Apple, Google, or Kobo specs) and a separate internal EPUB cover image.
  3. Check both exports for compression artifacts and confirm file size sits comfortably under each retailer's limit.
  4. Run EpubCheck or a retailer preflight tool against the packaged file to catch manifest or metadata errors.
  5. Open the finished EPUB on at least two device types or reader apps to confirm the cover displays correctly, both as a thumbnail and full page.

Kobo's own documentation notes that pushing a cover's pixel dimensions higher than its practical target stops improving anything past a certain threshold, which tells you where your time is better spent: not chasing bigger files, but getting the manifest, metadata, and standalone XHTML structure right. That's where covers actually break.

Where Alhora Fits Into a Cleaner Export Process

Most cover errors aren't design problems. They're packaging problems: a missing manifest property, a resolution that slipped below a retailer's floor, a media-type string that doesn't match the file. Real-time validation against publishing standards can help catch low-resolution images or manifest omissions before uploading, rather than after receiving a rejection email. Its typesetting engine handles export presets for retailer-ready marketing covers and separate internal EPUB covers, keeping the two files properly distinct the way Apple and Kobo both expect.

A Practitioner's Take on Pixels First, DPI Second

Build the large master, export tailored versions for each retailer, and stop treating DPI as the thing that makes a cover look sharp. Pixel count does that work. Retailer compression and real device testing catch the problems DPI settings never will.

— James

Try a Tool-Assisted Cover Export Workflow

Manually juggling five retailer specs, RGB checks, and manifest syntax is where most cover errors sneak in, and no amount of careful design work fixes a missing cover-image property after the fact. Alhora's ebook formatting software builds retailer-ready EPUB exports with real-time validation running against KDP, Apple Books, Google Play, and Kobo standards as you work, catching low-resolution images and manifest gaps before they become upload rejections.

Alhora

If Kindle is your primary platform, the KDP formatting workflow applies KDP-specific export presets automatically, so your marketing cover and internal EPUB cover both meet spec without you cross-referencing Amazon's documentation line by line. Alhora is a one-time purchase at $99 per license rather than a recurring subscription. Open your manuscript in Alhora and run a preflight check on your current cover file to see exactly where it stands before your next upload.

Official Platform Docs Worth Bookmarking

Retailer specs change without much announcement, so keep these bookmarked and recheck them before every upload: KDP's cover criteria, the Apple Books Asset Guide, Google Play's partner help center, and Kobo's EPUB guidance. For manifest syntax specifics, the images-in-EPUB reference covers embedding patterns in more depth than any single retailer's documentation.

Sources

FAQ

What Is the Ideal Image Size for an Ebook Cover?

The widely used target is 2,560 × 1,600 pixels at a 1.6:1 ratio, which matches Amazon KDP's ideal cover spec. Building your master at this size gives you enough resolution to export smaller, retailer-specific versions without losing sharpness.

What Size Should a Book Cover Image Be for Different Retailers?

It varies: KDP's minimum is 1,000 × 625 px, Apple Books wants at least 1,400 px on the shorter axis, Google Play uses a 1,024-pixel baseline, and Kobo suggests an average of 800 × 1,224 px at a 3:4 ratio. Designing one large master at 2,560 × 1,600 px and scaling down for each platform avoids maintaining separate source files.

Amazon KDP lists an ideal size of 2,560 × 1,600 px, a minimum of 1,000 × 625 px, and a maximum of 10,000 × 10,000 px, accepting JPEG or TIFF files. KDP also recommends minimal compression and a 300 PPI setting, though the pixel dimensions matter far more than the DPI number for how sharp the cover actually looks on screen.

Apple Books, Google Play Books, and Kobo each publish their own minimums rather than a single universal figure, so a cover sized only for Kindle can fall short elsewhere. Building a 2,560 × 1,600 px master and exporting per-platform versions, using tools like Alhora's export presets, covers every major store's requirements from one source file.