In case it has an effect, are you logged in or logged out on both browsers?

To rule out the contents of saved cookies, could you compare the results in a Firefox private window vs. a Chrome incognito window?

Thanks for the response, jscher2000.

Curiously, in a Chrome incognito window I lose the profile picture.

The search result in a Firefox private window is exactly the same -- no profile picture.

I hope this helps.

Thanks again.

I see author pictures on some results in Firefox when I am logged out and even in a private window, so at the most general level, you don't have to be logged in to Google+ or have previously set Google cookies to see them.

However, Google appears to make some decisions about displaying the photos. It says "Google will only show authorship in search results when we think it will be useful to the user." (1306778). Maybe the author of interest to you does not have a level of authority that Google feels warrants showing the picture to everyone, but if you are in a related circle then you see it??

Thanks again for looking into this, jscher2000.

I can understand that Google may choose not to display the author's profile picture. But one would expect that when this happens, then the resulting search results listing should be consistent -- no profile picture displayed -- regardless of the browser used.

In this case, the profile picture displays on Google Chrome, but not in Firefox nor in Internet Explorer. I may be wrong, but this leads me to think that this may be a browser-related issue.

Unfortunately, there's not much mention of it on the web.

I absolutely believe that Google sends different results pages to Chrome than to other browsers. But to get to the bottom of the reason for the difference, I think I would need to find an example where I get different results in order to explore it in more detail.

If you want to explore this further, consider posting an inquiry on Google support forum:

https://productforums.google.com/forum/#!categories/websearch