Check the image exceptions: Tools > Options > Content: Load Images: Exceptions - See Settings for web content, pop-ups, fonts, and languages

A way to see which images are blocked is to click the favicon (Site Identification icon) on the left side of the location bar. A click on the "More Information" button will open the Security tab of the "Page Info" window (also accessible via "Tools > Page Info"). Open the Media tab of the "Page Info" window. Select the first image and scroll down though the list with the Down arrow key. If an image in the list is grayed and there is a check-mark in the box "Block Images from..." then remove that mark to unblock the images from that domain.

See also Fix problems that cause images to not show and http://kb.mozillazine.org/Images_or_animations_do_not_load

This morning, around 3am, my facebook page suddenly went blank, then i tried to restart my pc and try again, the problem occurs again, then i have to use google search "facebook" and login, then only I am able to login to facebook, but when i press the "profile" button from firefox, it cannot load properly, help please...

"Clear the Cache": Firefox > Preferences > Advanced > Network > Offline Storage (Cache): "Clear Now" "Remove the Cookies" from sites that cause problems: Firefox > Preferences > Privacy > Cookies: "Show Cookies"

Start Firefox in Diagnose Firefox issues using Troubleshoot Mode to check if one of your add-ons is causing your problem (switch to the DEFAULT theme: Tools > Add-ons > Themes). See Troubleshoot extensions, themes and hardware acceleration issues to solve common Firefox problems and Troubleshoot issues with plugins like Flash or Java to fix common Firefox problems