added possibility to compare against a previously captured screenshot if using selector

1 files changed, 8 insertions, 1 deletions

diff --git a/tests/README.screenshots.md b/tests/README.screenshots.md
index b0189fe343..39648b1435 100644
--- a/tests/README.screenshots.md
+++ b/tests/README.screenshots.md
@@ -143,7 +143,14 @@ If you want to compare only parts (all content within an element / selector) of
             page.load(url);
         }, done);
     });
-    
+
+If you want to compare a screenshot against an already existing expected screenshot and capture a selector you can do the following:
+
+    it("should load correctly", function (done) {
+        expect.screenshot("screenshot_name").to.be.captureSelector("processed_screenshot_name", "#content", function (page) {
+            page.load(url);
+        }, done);
+    });
 
 ### Manipulating Pages Before Capture