I came across this problem a few days ago and some of my friends have been have too.

This is basically what it looks like.So I figured out a way to get around this.The fastest and easiest way to get around it is a quick browser change.Go to http://www.opera.com/download/ and download Opera.
Once you have it installed just go on facebook and it will ask you to approve some expired certificates on facebooks' image hosting servers.For some reason only some users experience , at least amongst my friends.
Just click approve every time it prompts you because facebook stores pictures on a lot of different servers.That's the fix i recommend because you'll have to go around and allow all facebooks' image servers manually on other browsers not like in opera with a few clicks.Although approving the servers on opera only lasts the session it just takes a few clicks.

Don't even bother trying to fix this on google chrome.You need to do everything manually and it only lasts the session.
For firefox find a blank image right click on it and View Image.
You should see something like this.Click I Understand the Risks then Add Exception... and a window should pop up with the link to the image.Delete everything after akamaihd.net and click Get Certificate.Then just Confirm Security Exception and all the images on the given server should work.Make sure you delete everything on the end of the link because then you'll only allow your browser to view the particular image not the images on the whole server.