H5P file size issue

Hi,

I am dealing with H5P file size issue.

I have a H5P presentation file that contains around 30 slides. The original file size of the complete presentation is 11MB, which seems to be appropriate.

However, when I split it into 4 shorter presentations, each file ends up being between 5-6MB. I have observed the unusual behavior where the file size increases dramatically just after saving, from 2-2.5MB to 5-6MB.

All the images and audio files used in the presentation are optimized, but I am unable to understand the cause of this issue.

I am using Lumi as my primary H5P editor on Windows 10. 

Can anyone suggest a solution or a way fix it, or to decrease the file size of the shorter presentations?

Thanks.