Computer locks up when converting libre odt to pdf help!

I have written a book that I am trying to convert for Kindle. I previously wrote the book in Openoffice. I have recently switched from Openoffice to Libre. I have been able to convert all other Libre odt’s to pdf’s without problems. Only since I have been tweaking the book to work properly for Kindle have I run into this problem. Since I have been trying to get the book to work in Kindle I have gone back and made some changes: I converted my graphs and tables from pdf’s to jpegs. Also some pictures I got off the internet previously had active links to my book - I saved those as jpegs also so they are now hard copied into my book. The only other thing I have done is added a clickable feature to the table of contents - When I first wrote the book, I had not used Headings I just entered the type size I wanted for the chapters. Before I made the above changes, I did not have a problem converting the book to a pdf.

I ended up deleting a particular picture I had gotten off the internet. Afterwards the file converted to pdf.

Thanks for comment the solution.