Do you know any Firefox addon that could download a whole website and download all the sites from the links on the first website? I mean also all images and so on.
Check out DownloadThemAll.
DownThemAll is fast, reliable and easy-to-use! It lets you download all the links or images contained in a webpage and much more: you can refine your downloads by fully customizable criteria to get only what you really want! Be in full control over your downloads, dedicated speed and number of parallel connections at any time. Use Metalinks or add mirrors manually to download a file from different servers at the same time.
I suggest using FoxySpider addon and configure it by adding:
To "other files" in the "content" option.
Consider the second null extension.