I use Nixnote to do what your trying to achieve not Libre Office.
If your question is “how can you do this in Libre Office” then ignore my answer. My answer is just an alternative that works best for me and many others. I do a lot of research and need to organize and review web pages (and all their content) regularly.
Nixnote (formerly Nevernote) is an open source clone of Evernote.
Evernote makes it easy to remember things big and small from your everyday life using your computer, phone, tablet and importantly for you the web.
For this solution you must use the Evernote (clipper) extension for Mozilla Firefox. (Available in FireFox Add-ons)
When you browse the internet using Firefox and you come across a website that you want to keep for review (text and Pictures), the EverNote clipper will allow you to this.
When you install NixNote on Ubuntu desktop you can set it up to automatically synchronize with your Evernote note book. The result will be that all your websites that you want to review will be in the NixNote desktop software.
You can get NixNote here
For more information on EverNote click here