How do I get IF ELSE to return an image?

I have this if else script that returns either "Correct" or "Incorrect"

How do I get it to return an image instead of text?

Images I wish to use are: Correct: http://ift.tt/214UI8r Incorrect: http://ift.tt/1PNpgmH

What is 1 + 1?<br>

Answer:&nbsp;<input type="text" length="3" id="ANSWER1A">
<input type="button" value="Enter" onclick="Q1A()">

<script language="javascript">
    function Q1A()
    {
        var A = document.getElementById("ANSWER1A").value;
        var A;
        if (A == '2') {
        R = "CORRECT";
    } else {
        R = "INCORRECT";
    } 
document.getElementById("RETURN1A").innerHTML = R;
    }
</script>

<p id="RETURN1A">