Source for image, before I added the words: http://saanichfusionfc.ca/wp-content/uploads/2015/06/Lightning_over_city.jpg
Source for the quote, itself: More Maxims of Mark, By Mark Twain, ed. Merle Johnson (New York: Privately printed, November 1927). See, also, this website.
I am grateful to my friend Tom, for helping me correct this Mark Twain quote, an earlier (and apparently incorrect) version of which I posted here.
Regarding the incorrect grammar in the quote: it’s Mark Twain. One does not correct the grammar of a great writer!