avatars on most websites not appearing

Suddenly this morning my own and most other user profile avatars on the reader comments threads of the news websites I most frequently visit are not displaying. In their place is that square "corrupted" icon. This is consistent across Chrome, Firefox, and Safari browsers. I don't even know where to begin to try to figure out if this is a software problem at my end or at the Internet's end.

These are the affected sites:

• Washington Post

• New York Times

• Duolingo (not a newspaper but I'm studying several languages and all of the user forums are indicating corrupted avatars

(For what it's worth, Twitter and my local newspaper, The Oregonian, are both displaying avatars correctly. )

Advance thanks for any theories, ideas and/or suggestions.