Lately Twitter has been having some problems with broken avatar and background images in Firefox. I traced it back to a problem with OSCP validation of https://si0.twimg.com and https://pbs.twimg.com. The symptom is that random avatars, images and backgrounds display as broken. It looks like this:
By copying the source URL of the image and going to it directly I was able to get Firefox to produce this error message:
Secure Connection Failed
An error occurred during a connection to pbs.twimg.com. The OCSP response contains out-of-date information.
(Error code: sec_error_ocsp_old_response)
Avatars help people quickly recognize all the accounts that they follow and are generally helpful so I wanted to get them back. To do this click on Options, Advanced, Certificates and finally Validation. As follows:
When the dialog box shows up uncheck “Use the Online Certificate Status Protocol (OCSP) to confirm the current validity of certificates.
Then press ok and ok again on the options panel. Reload Twitter and the avatars now show up.
This is only a temporary solution though since it does leave the browser open to man in the middle attacks. When you re-enable OCSP the avatars will continue to show up for a little bit and then start to fail again. Repeat the process and they’ll come back to life. This is probably a Firefox bug since on the same computer no other browser does this. It does seem to get better with the Firefox 25 beta build from today (October 22, 2013).