It is possible that you clicked "Block Images" in the right click context menu.
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

I have that problem too. It has nothing to do with "Block Images" option. Maybe an error occured when downloading make the image broken. Reload page, "load image" and "view image" doesn't work too. I must switch to other browser or clear firefox cache to view that image.

It is probably a bug

I'm having the same issue. I can click on and get an enlarged photo image when i use my facebook account on a XP system with Firefox. However, on my new laptop with Vista and Firefox, the pictures do not load. Did you find any resolution? I've been searching websites for suggestions for an hour to no avail. Thanks so much!

I have the same problem. I am using IMack desktop and have no problem with photos/Facebook using Safari and Google Chrome. Firefox will not load the pic when I click on it. I have uninstalled Firefox and reinstalled. Also left Facebook and came back twice. Problem still there.

cor-el is correct. i had somehow blocked the images from Facebook. I too it off the blocked list as he advised. Problem solved!!! Thanks.

I'm having the same issue. I ONLY have this problem on my laptop using Firefox 3.6.8 (& Vista). The photos display immediately when I use facebook on the same laptop with Internet Explorer. I can also see the photos when I use FB on my desktop with Firefox and XP.

Please post resolution if you found it. I can't find anything helpful on any other websites. Thank you !!!

Did you check the exceptions?

See also Fix problems that cause images to not show

Thank you cor-el

I have the problem and the exceptions suggestion hasn't worked. I'm using XP, and all of the latest software. Unfortunately, I'm not a computer geek. I get around OK, but it doesn't take much to befuddle me. This happened night before last without my having changed any settings intentionally. There are so many options, between Facebook, Firefox, its addons, like ABP and XP that I can't find what may be causing the problem. I've disabled ABP so I feel it is not the problem.

I've also sent a report to Facebook with screen shots, as requested, but have not heard from them, nor found any response that indicates they have read my complaint.

I know Users get blamed for being idiots, but sometimes there are limits to what a fellow has been exposed. Thanks for the exceptions hint, keep'em coming.

I had the same problem and tried all image loading settings to no avail. Just find some good uninstaller software and use it to remove everything Firefox, and then re-install Firefox 4, bang!!!! all images are back on Facebook. I am enjoying Firefox 4.