A.html Código HTML:
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
<title>Untitled Document</title>
</head>
<body>
<script language="javascript">
function CambiarImg() {
window.frames["MiIframe"].document.getElementById("Imagen").src = "carpeta/otra_imagen.jpg"
}
</script>
<input type="button" value="Cambiar Imagen" onClick="CambiarImg()">
<iframe src="b.html" name="MiIframe" id="MiIframe" frameborder="0" width="100%" height="400"></iframe>
</body>
</html>
B.html Código HTML:
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
<title>Untitled Document</title>
</head>
<body>
<img src="unaimagen.jpg" id="Imagen">
</body>
</html>
saludos
