Many site issues can be caused by corrupt cookies or cache. In order to try to fix these problems, the first step is to clear both cookies and the cache. Note: This will temporarily log you out of all sites you're logged in to. To clear cache and cookies do the following:

1. Click the menu button , choose History, and then "Clear Recent History...".
2. Under "Time range to clear", select "Everything".
3. Now, click the arrow next to Details to toggle the Details list active.
4. From the details list, check Cache and Cookies and uncheck everything else.
5. Now click the "Clear Now" button.

Further information can be found in the Delete browsing, search and download history on Firefox article.

Did this fix your problems? Please report back to us!

If images are missing then check that you aren't blocking images from some domains.

See:

http://kb.mozillazine.org/Images_or_animations_do_not_load

   Check the permissions for the domain in the current tab in Tools > Page Info > Permissions
   Check that images are enabled: Tools > Options > Content: [X] Load images automatically
   Check the exceptions in Tools > Options > Content: Load Images > Exceptions
   Check the "Tools > Page Info > Media" tab for blocked images (scroll through all the images) 

There are also extensions (Tools > Add-ons > Extensions) that can block images.