Recently, we've seen users getting that error message because the image is incredibly tall (or incredibly wide) and exceeds Firefox's maximum image size of about 32,766 pixels in height or width.* In those cases, the file isn't bad, but it can't be displayed in Firefox. You might be able to download it and view it in an image viewer instead. I am not aware of a good workaround for that issue.

If this doesn't sound like a case where the image is too large, do you want to post a URL to the page that has the problem?

* This maximum only seems to affect Windows versions of Firefox.

Note that the message that the "image can't be displayed" is actually a placeholder message that Firefox shows as long as the full image hasn't been loaded from the server.

You can reset user set (bold) network.http.* prefs on the about:config page via the right-click context menu to the default value.

• http://kb.mozillazine.org/network.http.pipelining

If images are missing or corrupted 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 checkmark then remove this checkmark 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

I tried this:

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 checkmark then remove this checkmark to unblock images from this domain.

The image doesn't have a checkmark next to it. Now what?

You do see all the images in "Tools > Page Info > Media" or are some missing that should be there?

Does the Page Info dialog show the image size and dimensions for that image, or is that information not available?

If you use Save As on the image* and open it in an image viewing/editing program, does it look correct or garbled, or does that program indicate a problem with the file?

* From the Page Info dialog

They don't appear in the "page info" area.

It shows the dimensions but it says the size is "unknown". I haven't tried saving the image.

Hello?

Does it show the image itself in the preview pane?

As I posted above, this specific message (this image can't be displayed because it contains errors) is a placeholder message that Firefox shows while retrieving the image form the server and once this has finished this message is replaced by the real image. If you keep seeing this message then Firefox wasn't able to load the image.

You can check the Net log and the Network tab in the Web Console (Firefox/Tools > Web Developer) to see if there are errors showing with these images.

• https://developer.mozilla.org/Tools/Web_Console

Regarding this "preview pane". Do you mean the "media preview" area when I go to "Tools > Page Info"?

Yes.

Do you see any images there in "Tools > Page Info > Media"?

Do they show if you copy and paste their URL in the location bar?

Click the location field and use Ctrl+A and Ctrl+C to copy long URLs more easily.