Re: Firefox cannot display certain images and shows "This image <image> cannot be displayed because it contains errors."
"This image <image> cannot be displayed because it contains errors." is a place holder message that gets replaced by the image when Firefox is ready to render this.
Can you post a link to a publicly accessible page that doesn't require authentication (signing on)?
Start Firefox in Safe Mode to check if one of the extensions (Firefox/Tools > Add-ons > Extensions) or if hardware acceleration is causing the problem (switch to the DEFAULT theme: Firefox/Tools > Add-ons > Appearance).
Do NOT click the Reset button on the Safe Mode start window or otherwise make changes.
You can inspect and manage the permissions for all domains on the aboutermissions page or for the current domain via the "Site Identity Button" (globe/padlock on location bar) and click "More Information" to open "Page Info" and go to the Permissions tab.