The image is an illustration of the Bastille, the storm of which is seen as the culmination of the French Revolution, a massive triumph of evil over good. However, Diderot was speaking of the American Revolution, quite a different historical context.
I took the quote of Diderot from a book about JFK by a French author. I copied it exactly as written in that book. It was the only book I have ever seen the quote in.
As far as the illustration, after thinking about it a while, I came to the conclusion I copied the photo from a book on gutenberg.org.
Now, I had no idea the quote was aimed at the American Revolution when I put the 2 together. And that was long ago.
Thank you for making the connection. As you said, the Storming of the Bastille was a number of years later.
As far as accuracy of the quote, it may be due to translation. I am pretty sure it was originally written in French, which I do not speak.
But I am puzzled about your statement: “a massive triumph of evil over good”.
I agree there was great evil at the end of the French Revolution. But I see nothing “good” about French Aristocracy.