Downloads Size of Bloom Books

The size of Bloom books available for downloads are ever so large. A few pages can run into Megabytes in size. Ebooks in other formats will normally be smaller. Is there no way these books can be compressed to make them smaller for downloads?

Hi Katelem,
It would be interesting to do an apples to apples comparison. Can you point me to a book in a different format that you would like us to compare?


I mean that if I type the same story in MS Word, with images, and convert to PDF, the size will be smaller, in few hundred kb. But in Bloom book, the same story will be in Megabytes.

One can confirm by using the Publish Tab to build a book in different format such as .pdf, .epub, .bloom, etc. The .bloom is always larger than the other formats, and it’s the .bloom that goes to the bloom library and gets downloaded into the Bloom Reader.

I’ve found what makes my Bloom books so large is the images I choose to use. The Art for Reading Library’s images are vary small. But if I choose external images and don’t compress them down small enough, it drives the book size up quickly. Perhaps the .pdf export on Word is compressing the images more than Bloom is? It might be nice to have a way for Bloom to highly compress images. It would save the user much time in trying to compress each image BEFORE inserting into Bloom.

When I download books off Bloom Library which are too large, I compress all the images and can significantly shrink the book down. Just more work!

Yeah, @Casey_Ellis we could do that. We do already automatically scale images down in some situations:

When you add an image to a page, Bloom reduces its resolution to what would be a full-size, 300 dpi image if printed on A4 paper. This works out to about 2550 x 3500 pixels.

When you publish a book to ePUB, BloomPUB, or the web, Bloom reduces images to a max of 600 x 600 pixels.

So, some questions:

  • Are you wanting this for PDFs as well? I think we could safely auto-reduce to 600dpi without asking.

  • If we gave an option to further reduce the ebooks formats, we’d need to do it in a way that people can make a good decision. A simple choice “x by y pixels” would be too technical for most people… they wouldn’t know how many pixels are in phones, or tablets, or the web. So maybe some kind of “normal”, “compressed”, “super-compressed” option?

So the compression only happens at publication? I have been using SAB to point to the source .htm file within the Bloom directory. I’ve done this so that if I edit the text of the book in Bloom I can do a “update from org. source” in SAB and have an auto update for my books in the app. If I had to export and save each individual book as a .bloommd file, it would take a LONG time and I couldn’t update my books easily.

Secondly, I did a test and the file is larger as a .bloommd file than if I use the .htm source file only. When adding a book to SAB using a bloom file it puts the boom file AND the unpackaged file contents in the book folder within SAB. When I have 80 books in the app it creates a lot of unnecessary data.


@Casey_Ellis do you already have a Bloom Enterprise subscription? Please write to me if not. Yeah we do not support the kind of direct linking you’re doing. It may work, may not… not supported.

Using Bloom 5.1 with a BE subscription, you can do bulk publishing of all your bloomPUBs, which would be efficient.

Thanks for this, good to know. Is Bloom 5.1 released yet? That bulk publishing would be a GREAT time saver :slight_smile: Casey

Is Bloom 5.1 released yet?

Bloom 5.1 beta is delayed a bit by a few final issues, but it’s basically done, and you can get it here.