LoolGram,
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>JS Bin</title>
<script>
</script>
</head>
<body>
<img src="https://cdn0.iconfinder.com/data/icons/small-n-flat/24/678069-sign-error-32.png">
<img src="https://cdn0.iconfinder.com/data/icons/small-n-flat/24/678134-sign-check-32.png">
<form name="quiz" >
<table id="table" style="font-size: 24px;">
<tr>
<td>а | аа </td>
<td>
<select name="q1" class="ComboBox">
<option value="">Выберите</option>
<option value="1">ой</option>
<option value="2015">ай</option>
<option value="3">эй</option>
<option value="4">уй</option>
<option value="5">ы</option>
<option value="6">үй</option>
</select>
</td>
<td>
<img height= 32px width=32px>
</td>
</tr>
<tr>
<td>э | ээ</td>
<td>
<select name="q2" class="ComboBox">
<option value="">Выберите</option>
<option value="1">ой</option>
<option value="2">ай</option>
<option value="2015">эй</option>
<option value="4">уй</option>
<option value="5">ы</option>
<option value="6">үй</option>
</select>
</td>
<td>
<img height= 32px width=32px>
</td>
</tr>
<tr>
<td> о | оо</td>
<td>
<select name="q3" class="ComboBox">
<option value="">Выберите</option>
<option value="2015">ой</option>
<option value="2">ай</option>
<option value="3">эй</option>
<option value="4">уй</option>
<option value="5">ы</option>
<option value="6">үй</option>
</select>
</td>
<td>
<img height= 32px width=32px>
</td>
</tr>
<tr>
<td> и | ии</td>
<td>
<select name="q3" class="ComboBox">
<option value="">Выберите</option>
<option value="1">ой</option>
<option value="2">ай</option>
<option value="3">эй</option>
<option value="4">уй</option>
<option value="2015">ы</option>
<option value="6">үй</option>
</select>
</td>
<td>
<img height= 32px width=32px>
</td>
</tr>
</table>
<input type="submit" value="Проверить" >
</form>
<script>
function fn(event) {
event.preventDefault();
var trs = this.querySelectorAll("tr");
[].forEach.call(trs, function(el) {
var val = el.querySelector(".ComboBox").value,
img = el.querySelector("img");
img.src = "https://cdn0.iconfinder.com/data/icons/small-n-flat/24/" + (val == "2015" ? "678134-sign-check-32.png" : "678069-sign-error-32.png")
})
};
document.forms.quiz.addEventListener( "submit" , fn, false);
</script>
</body>
</html>