How to reduce the size of an ePUB file

[Cov]

Hi,

I wonder how this is possible:

Just downloaded an epub with 194 pages that is 270 MB big

TPB

workerbee edited Sep 29, 2017 15:55 pm this post because: Thread title edited for clarity.

[workerbee]

If you downloaded it, you will have noted that the book features more than 200 full-color plates of book covers. That's why the file is so large.

[Cov]

ok, I see

I wonder if the resolution of those images could be reduced, to make the ebook smaller, ... like maybe around 30 to 40 MB instead of 270 MB.

[workerbee]

You could do that, although in most cases it is not necessary.  Remember that an EPUB file is really just a zip file that compresses the HTML, CSS, and other content files into one package.  So:

1. Rename the file's extension from .EPUB to .ZIP.

2. Extract the archived file.

3. Inside the extracted folder you will find all the individual JPG and other images.  You may reduce each of these to your desired size.

4. Finally, recompress all the folder's contents into a new .ZIP file.  Rename the extension again, this time from .ZIP back to .EPUB

You should have a much smaller EPUB file but you may find the lower resolution images unsatisfactory.  And of course the result can no longer be called "retail" because you've altered it.

For more, see https://ebooks.stackexchange.com/questio...-mobi-file

EDIT - Before you try this for the first time, make sure you are working on a copy of the original file.

[Cov]

Thanks very much for this great information!


- I've renamed the extension epub to rar
- extracted the file (resulting in 2 folders, 2 sub folders and several files)


one of the folder called "images" (274 MB) contained 216 images
meaning the ebook itself (without any images) is only 613 Kb big!
it's so cool to know this.