The search option that produced large snippets (tbs=sts:1) now produces the message "The search option you have selected is currently unavailable."

google.com/search?tbs=sts:1&am ...

It has been replaced by "page previews".

I don't have "page previews", and George's link works for me.
I think it's a test from Google because I can see "page previews" with another Google account.

Here is a link using the search option for page previews (tbs=prv:1).
google.com/search?tbs=prv:1&am ...

It seems to produce both large snippets and an image.
The image shows partial renderings of some of the matched pages.