How to Unblock images on Firefox?
If you right click on an image in Mozilla Firefox, there is an option to block all images from that particular website. Often users click it accidentally, and then can’t see images from blocked websites.
But how can you UNDO this?
Very simple, here is how:

softize 9:30 am on August 19, 2010
1. Open Firefox.
2. Go to Tools > Options > Content
3. You should find a button labeled “Exceptions” next to the “Load Images Automatically” checkbox. Click that button.
4. Now a dialog box should appear which contains all URL-s that are blocked.
5. Select the URL you want to unblock images from, and then click “Remove Site” button. Or click “Remove All Sites”.
Now firefox should not block images anymore.