The image in this code should show if flash isn't installed.
Code:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<title></title>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
</head>
<body>
<object type="application/x-shockwave-flash" data="movie.swf" width="400" height="300">
<param name="movie" value="movie.swf">
<img src="nonflashimage.jpg" title="Your browser doesn't have flash installed" alt="Your browser doesn't have flash installed">
</object>
</body>
</html>