NO FUNCIONA, puse esto:
<html>
<head>
<script language="JavaScript" type="text/javascript">
function pasa ( ) {
var indice=document.forms.formulario.select1.options.s electedIndex;
var valor=document.forms.formulario.select1.options[indice].value;
var texto=document.forms.formulario.select1.options[indice].text;
var indice2=document.forms.formulario.select2.options. selectedIndex;
var valor2=document.forms.formulario.select2.options[indice2].value;
var texto2=document.forms.formulario.select2.options[indice2].text;
var indice3=document.forms.formulario.select3.options. selectedIndex;
var valor3=document.forms.formulario.select3.options[indice3].value;
var texto3=document.forms.formulario.select3.options[indice3].text;
document.write(valor);
document.write(valor2);
document.write(valor3);
if (valor == '0k' && valor2 == '1v' && valor3 == '10k'){
document.getElementById('foto').innerHTML="<img src='imagenes/gra7.jpg'>";
}
}
</script>
</head>
<body>
--TEXTO PRINCIPAL ----dfgdsgdgdfgdfgg sdfgsdfgsdfgdsfgdsf sdfgdfgdsf sdgdsgsd gdsfg dsg sdgdsfg sdgfsdfg
fhgdfhs gfh fghg dfhgdf hdf hdf fd hdfh fdghdf hdfh dfh
hfghfghfdh dfh fh fh fdhj hdf <br><br><br>
<span id="foto"></span>
<form name="formulario" method="post" action="">
<select name="select1" size="1" id="select1">
<option value="0k">0k</option>
<option value="20k">20k</option>
<option value="30k">30k</option>
</select>
<select name="select2" size="1" id="select2">
<option value="1v">1v</option>
<option value="2v">2v</option>
</select>
<select name="select3" size="1" id="select3">
<option value="10k">10k</option>
<option value="50k">50k</option>
</select>
</form>
<input type="button" value="pasa valores" onClick="pasa()"><br><br>
</form>
</body>
</html>