Do you have that problem when running in the Firefox SafeMode?
http://support.mozilla.com/en-US/kb/Safe+Mode
Don't select anything right now, just use "Continue in SafeMode."

If not, see this:
http://support.mozilla.com/en-US/kb/troubleshooting+extensions+and+theme...

this really helped thanks

When trying to save a photo or picture in FACEBOOK, when the photo is up on your screen in FB's "black" viewer panel,,,hit the REFRESH BUTTON. It will take that photo back to FB's older version. You can capture them from there instead of in FB's "speacial black" viewing panel. This is NOT a Firefox thing,,,it's FACEBOOK constantly changing things on almost a daily or weekly basis.