Makes my site crash

I use this plugin to show a book that my client authored and so far it has been a nightmare. The end result is great but getting there is a massive headache.
When you change some settings in the “page editor” window, they don’t stick and you have to keep trying to change them. It also has a hard time uploading a lot of images at once. I wish it had a pdf capability, but it doesn’t.
Also, since the book I have on there is 158 pages (but very small file sizes, 50kb or less), the plugin is making my admin side of my website crash and have the “500 Internal Server Error” constantly. I can’t even get into the admin side to change anything or disable the plugin. I will be looking for a more reliable plugin to do the job I need without so many issues and bugs.