Image File Requirements and Best Practices: Filename, Format, Image Size

Because a Hederis book project can be output as PDF, EPUB, HTML, and .docx, we limit the image file formats you can upload to your project to those with broad support in web browsers and ebook readers.

Accepted File Formats

Images can be replaced by uploading a new image file, or editing the text in the Hederis Edit Text pane or the Word file.

Currently, Hederis only supports uploading of PNG or JPEG files with the following file extensions:

  • .jpeg

  • .jpg

  • .png

If you pick or drag and drop any other type of image file (a tiff or gif, for example), you will see the pop-up warning, “You can only upload .docx and image files” and your image will not be added to your project.

File Naming Tips

Hederis will automatically place image files you upload to your Hederis project into the flow of your book if the filename of your uploaded file exactly matches the filename specified in your original doc or docx manuscript file (see Add an image in Word). You can also edit the filename specified in your uploaded Hederis project to match the name of an uploaded file (see Replace or delete an image for details).

It is important to note that if your image filename contains spaces or capital letters, the app will automatically “slugify” the name, making all letters lowercase and replacing whitespace characters with an underscore (“_”). If you have problems with your uploaded image displaying in your Design Preview, check that the filename and the filename referenced in your text match.

Image Size Requirement for Print and EPUB

The resolution of your images will be preserved as-is in any PDF you output from your Hederis project. The only restriction for images in any EPUB you generate is that images will be automatically scaled down to no larger than 1,000,000 pixels total for the non-Kindle EPUB (as required by Apple). For information on creating full page images that bleed off the printed page, see Include full-page images in the PDF.

Ereader devices and apps offer varying support for controlling image sizes. In some devices or apps, you can specify the size using any type of measurement (points, pixels, percentages), and that size will be preserved (iBooks is one such app). In others, you can only use fixed unit types for your image size, like points, pixels, or inches, but not percentages (Kindle is an example of this type).

Adjust letter spacing by tightening and loosening text (PDF-only)
Types of images: block and inline
Getting Started
Step-by-Step Guide
File Management, Uploads, and Downloads
Working with Book Text
Validation and Preflight
Groups and Billing
How Do I…