Автор, с тебя футомаки.
<!DOCTYPE html>
<html lang="ru">
<head>
<meta charset="UTF-8">
<title>Document</title>
</head>
<style>
.bg {
background-image: url(http://th08.deviantart.net/fs5/150/i/2004/332/1/c/PIKA_by_spocha.jpg);
height: 100px;
background-size: contain;
background-repeat: no-repeat;
}
</style>
<body>
<input type="text">
<div class="bg"></div>
<script>
var words = ['футомаки', 'суперфутомаки'];
var urls = ['http://dostavka-pizza.kiev.ua/simg/136-176-home.jpg',
'http://www.food24.com.ua/imageshandler.ashx/Products/7/600/500/tnh_51b.jpg'];
var searchWord = document.querySelector('input');
var bg = document.querySelector('.bg');
searchWord.addEventListener('keyup', function() {
var indx = words.indexOf(searchWord.value);
if (indx >= 0) {
console.log(urls[indx]);
bg.style.backgroundImage = 'url(' + urls[indx] + ')';
searchWord.value = '';
}
}, false);
</script>
</body>
</html>