If you use extensions (Firefox/Tools > Add-ons > Extensions) that can block content (e.g. Adblock Plus, NoScript, Flash Block, Ghostery) then make sure that such extensions aren't blocking content.

If images are missing then check that you do not block images from some domains.

• Press the F10 key or tap the Alt key to bring up the hidden Menu bar.

Check the permissions for the domain in the currently selected tab in "Tools > Page Info > Permissions"

Check "Tools > Page Info > Media" for blocked images

• Select the first image link and use the cursor Down key to scroll through the list.
• If an image in the list is grayed and "Block Images from..." has a check-mark then remove this check-mark to unblock images from this domain.

Make sure that you do not block (third-party) images, the permissions.default.image pref on the about:config page should be 1.

Make sure that you haven't enabled a High Contrast theme in the Windows/Mac Accessibility settings.

Make sure that you allow pages to choose their own colors.

• Tools > Options > Content : Fonts & Colors > Colors : [X] "Allow pages to choose their own colors, instead of my selections above"

Note that these settings affect background images.

See also:

• http://kb.mozillazine.org/Website_colors_are_wrong

There are extensions like Adblock Plus (Firefox/Tools > Add-ons > Extensions) and security software (firewall, anti-virus) that can block images and other content.

See also:

• https://support.mozilla.org/kb/Troubleshooting+extensions+and+themes
• http://kb.mozillazine.org/Images_or_animations_do_not_load
• http://kb.mozillazine.org/Websites_look_wrong

Thank you for your response. I've tried disabling AdBlock Plus, but that hasn't fixed the disappearance of images on this site. I have the Windows firewall as a default but also use a free anti-virus and firewall. I just don't follow why in IE (which I really dislike) the website works fine with all my settings, but not in Firefox or Chrome. I will go back and try your suggestions as I've not gotten around to it yet, and follow up with some progress, hopefully.

You can remove all data stored in Firefox from a specific domain via "Forget About This Site" in the right-click context menu of an history entry ("History > Show All History" or "View > Sidebar > History") or via the about:permissions page.

Using "Forget About This Site" will remove all data stored in Firefox from that domain like bookmarks, cookies, passwords, cache, history, and exceptions, so be cautious and if you have a password or other data from that domain that you do not want to lose then make sure to backup this data or make a note.

You can't recover from this 'forget' unless you have a backup of the involved files.

It doesn't have any lasting effect, so if you revisit such a 'forgotten' website then data from that website will be saved once again.