How to Compress a Bloom PDF

Edit: This should not be needed, starting with Bloom 4.0.106


Bloom uses its built-in Firefox browser to make PDFs. Unfortunately that process takes nice, well-compressed jpegs and pngs and decompresses them. The resulting file is MUCH larger than your original book. For example, a 2mb book of 3 photos can be a 60mb pdf.

Ideally, Bloom will someday have a way to do its own compression. But in the meantime, it’s not hard for you to do this yourself. The following instructions take the file back down to about the size of the original book.

Note: These steps are for Windows. If you’d like steps for Linux, let us know (or if you’re techincal, just see here).


A) Download and Install gsview

B) In Bloom Publish tab, make the PDF, then save it somewhere

C) In GsView, choose File:Open, choose the PDF you created in step A

D) In GsView, choose File: Advanced Conversions

E) Do these three steps:

  1. Click ‘pdfwrite’

  2. Click “All Pages”

  3. Click “Convert”

GSView will ask you where to save the pdf. After the PDF is saved, please open it in your PDF reader and check it over carefully, including the fonts. Should you find any discrepancy, please notify us immediately by sending an email to In the future, we will likely be building this into Bloom, and need to know if there are any unwanted side-effects.