diff --git a/README.md b/README.md
index 6e75ded..30d54a2 100644
--- a/README.md
+++ b/README.md
@@ -107,6 +107,7 @@ ext-js      | List of external JavaScript files to include in the page (eg. `//c
 css         | List of local CSS files to include in the page
 ex-css      | List of external CSS files to include in the page
 googlefonts | List of Google fonts to include in the page (eg. `["Monoton", "Lobster"]`)
+fb-img      | If you want to share a page on Facebook, by default Facebook will use the first image it can find on the page.  If you want to specify an image to use when sharing the page on Facebook, then provide the image's URL here
 
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