Double image using rollover button

Image of concern: Russian Flag Go here for example http://www.progresslanguage.com/index_test_page.php I am using a “Rollover” button and my Russian flag image and hover image both show up. They are both .png format I tried placing images in Navbar File and then in the Images folder Now it is published in a test page Tried in Firefox, IE, Safari and Opera with same or similar dual images showing What am I doing wrong?

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Double image using rollover button