Sizing and Manipulating Images for Pressbooks

We get a lot of questions about importing images into Pressbooks. We thought we’d answer those here.

How to Size Your Images for Ebook Production

Before you upload your images into Pressbooks, you’ll want to make them as small as possible while still retaining quality. Why? Bookstores charge you a delivery fee based on the size of your book in megabytes, and images make your book larger. Kindle, for example, charges you 15 cents per megabyte for every sale you make. And, our ebook plan is limited to 5 MB of storage. You could easily exceed that with just a few photos if you don’t resize them before uploading.

If you’re doing an ebook only, you can make your images smaller than you could if you’re doing both ebook and print. For ebooks, we suggest not making images larger than 250 KB. In terms of dimensions, 1:1.5 is a safe ratio.

There are many tools you can use to resize your images outside of Pressbooks. Many people use Photoshop. But if you don’t have that, there are plenty of free and low-cost apps out there that will let you resize and edit your photos online, from your desktop or on mobile. One such tool is Pixlr, which has both free and low-cost apps you can use.

Updated! Sizing Your Images for Ebook and Print

In Pressbooks, you’ll upload the same images just once for ebook and print. If you’re going to do both an ebook and a print book, we recommend keeping the images you upload around 1-2 MB per file (files cannot be over 2 MB to upload into Pressbooks) and 300 dpi. Our experience is that images of that size render fine in print. Make sure you select “full-size” in the image editor, otherwise a smaller/compressed version of the image will be exported.

To make sure you’re not charged for larger photos in your ebook, check the option under Appearance / Theme Options / Ebook Options to compress your images in the ebook export.

How to Upload Images in Pressbooks

We have a chapter in our User Guide on how to upload images into the Pressbooks interface. You can also check out our video tutorial on the subject. 

How to Edit Images in Pressbooks

If you don’t have image editing software, you can edit images from within Pressbooks. This User Guide chapter will show you how.

Photo Books, Children’s Books and Illustrated Books

Pressbooks does handle images, but it’s not necessarily the best tool to do image-only, or heavily designed books. It’s built for text with images … but not to make picture books.

That said, if you’re willing to do some custom coding and trial and error, you may be able to hack something. We suggest you play around and see if you get what you like.

4 thoughts on “Sizing and Manipulating Images for Pressbooks

  1. Would love more info on images for print. The 300dpi images I’ve uploaded haven’t translated to print (they come out grainy.) Help. Didn’t have this issue with a word doc.

  2. Totally agree. I have uploaded images, which look great when I zoom in etc – just as they are outside of Pressbooks – but are very grainy when inside the document !

  3. I think I’ve got it. You have to do “link to media file” else you just get the thumbnail. This could be made clear in the video etc.

  4. We are working on improving this. In the meantime, here’s a workaround. Adding the following code will force a 300-dpi output.

    Go into your Custom CSS>>
    Go to PDF output
    Add at bottom:

    img {prince-image-resolution: 300dpi !important;}

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