Why Image Formatting Matters for EPUB Conversion
Images are one of the trickiest elements to get right when converting a Word manuscript to EPUB. Unlike print PDFs, ebook readers display images at unpredictable sizes—a smartphone screen is nothing like a tablet, and reflowable text means your carefully positioned illustration might end up in the wrong place entirely.
The good news: if you format images correctly in Word before conversion, most tools (including ebookconvert.pro) will handle the heavy lifting. The bad news: small mistakes in Word can cascade into broken layouts, stretched images, or missing captions when your EPUB lands on an Apple Books reader's device.
This guide walks you through the exact steps to prepare images for EPUB so they look professional on every screen.
Before You Start: Image File Types and Resolution
Not all image formats are equal in the ebook world. EPUB 3 supports a limited set of file types, and resolution matters more than you might think.
Supported Formats
- JPEG (.jpg) — Best for photographs and complex artwork. Smaller file size, good quality.
- PNG (.png) — Best for illustrations, diagrams, and graphics with transparency. Larger files but sharper.
- SVG (.svg) — Vector format, scales perfectly on any device. Ideal for logos, maps, and line drawings.
Avoid BMP, TIFF, GIF, and WebP formats in your Word manuscript. They'll either fail during EPUB conversion or create compatibility problems on older readers.
Resolution Guidelines
For ebooks, you don't need the 300 DPI print standard. Aim for:
- 72–96 DPI for screen display (standard web resolution).
- Max width: 600 pixels for reflowable EPUB (accounts for the smallest tablet screens and margins).
- File size under 500 KB per image to keep your total EPUB under 100 MB.
If your image is larger, resize it before inserting it into Word. This prevents bloated EPUB files and ensures consistent rendering across devices.
Inserting Images into Your Word Manuscript
The method you use to insert images in Word directly affects how they'll behave during EPUB conversion. Do this wrong, and your image might anchor to a random paragraph or float off the page entirely.
Step 1: Insert as Inline with Text
Always use Insert > Pictures (not Insert > Shapes or Insert > Text Box). This embeds the image as an inline object, which EPUB converters understand.
Once inserted, right-click the image and select Wrap Text > Inline with Text. This is critical. Do not use "Square," "Tight," or "Behind Text" wrapping—these create floating objects that EPUB readers struggle to interpret.
Step 2: Resize Within Word
Don't rely on your image editor's dimensions. Resize the image inside Word to match your layout. A good rule of thumb:
- For full-width images: set width to 5.5 inches (leaving room for margins).
- For side-by-side images: set width to 2.5–3 inches each.
- For small spot illustrations: 1–2 inches.
Right-click the image, select Size and Position, and lock the aspect ratio. This prevents distortion.
Step 3: Anchor Images to Paragraphs
In Word, every floating or inline object is anchored to a paragraph. For EPUB conversion, make sure each image is anchored to a paragraph that will stay nearby during reflowing.
Best practice: place the image immediately after a paragraph of text (like a chapter heading or a descriptive sentence). Avoid orphaning images at the end of a section where they might drift away on mobile devices.
Adding Captions and Alt Text
Captions serve two purposes: they improve readability and they're essential for accessibility. Alt text is read aloud by screen readers, so don't skip it.
Captions in Word
Right-click your image and select Insert Caption. Use a consistent label (e.g., "Figure 1," "Illustration 2"). Word will auto-number them, which is helpful if you reference images in your text.
Format captions with a smaller font size (10–11 pt) and italics to distinguish them from body text. This also helps EPUB converters recognize them as captions rather than regular paragraphs.
Alt Text for Accessibility
Right-click the image, select Alt Text, and write a brief description (50–125 words). Be descriptive but concise:
- ❌ "Image of a cat."
- ✅ "A tabby cat sitting on a windowsill, looking out at a rainy garden."
Alt text isn't visible in your EPUB, but it's crucial for readers using screen readers and for SEO if your ebook is distributed widely.
Handling Multi-Image Layouts
If your manuscript includes image galleries, photo essays, or side-by-side comparisons, EPUB's reflowable nature makes this tricky. Here's how to handle common scenarios:
Image Series (Gallery Style)
If you have 3–5 images that should appear together, insert them as a series of inline images separated by line breaks (not paragraph breaks). In Word, use Shift+Enter to create a soft line break between images. This keeps them grouped together during EPUB conversion.
Side-by-Side Comparison Images
EPUB doesn't support true side-by-side layouts on small screens. Instead, stack images vertically and use captions to explain the comparison. For example:
"Figure 3a: Before restoration" [image]
"Figure 3b: After restoration" [image]
This works on every device, from a phone to a tablet.
Image-Heavy Sections (Cookbooks, Art Books)
If your book is heavily illustrated, consider using a table to control image placement. Create a borderless table with one cell per image. This gives you more control over sizing and alignment during EPUB conversion.
Common Mistakes to Avoid
- Using text boxes for images: Text boxes don't convert well to EPUB. Always use Insert > Pictures.
- Embedding images with "Behind Text" wrapping: This creates floating objects that EPUB readers misinterpret.
- Oversizing images in Word: A 6-inch-wide image will be too large for mobile EPUB readers. Stick to 5.5 inches max.
- Mixing image formats inconsistently: Stick to JPEG or PNG throughout your manuscript. Don't mix BMP, TIFF, and GIF.
- Forgetting captions on important images: Captions improve readability and help readers understand context.
- Placing images in headers or footers: EPUB doesn't support headers/footers. Move all images to the main document body.
Testing Before You Convert
Before uploading your manuscript to a converter, do a quick sanity check in Word:
- Open your manuscript and scroll through every image.
- Verify each image is set to Inline with Text (not floating).
- Check that captions are present and formatted consistently.
- Make sure no image is wider than 5.5 inches.
- Confirm alt text is filled in for all images.
If everything looks good in Word, it should convert cleanly. Tools like ebookconvert.pro automatically detect images and embed them correctly during EPUB generation, but clean source files always produce better results.
After Conversion: Validation
Once you've converted your Word manuscript to EPUB, open the file in an EPUB reader (Apple Books, Kindle Previewer, or a free reader like Calibre) and check:
- Do images appear on the correct pages?
- Are captions positioned correctly?
- Do images scale properly on different screen sizes?
- Is alt text visible when you hover over images (in readers that support it)?
If something looks off, go back to your Word file, adjust the image formatting, and reconvert. Most image issues are fixable with a quick tweak to sizing or wrapping.
Final Thoughts
Image formatting isn't complicated, but it requires attention to detail. By following these guidelines—using inline images, sizing appropriately, adding captions and alt text, and testing before conversion—you'll ensure your illustrations look professional across every EPUB reader and device. The extra 10 minutes spent formatting images in Word saves hours of troubleshooting after conversion.
