remover button file

[davidpereira]

<form onsubmit="return validar(this);" method="post" action="registo.php">
<div id="form_login">
<input type="file" id="user"/>
<div id="formulario_registo">
<input type="text" name="nome" placeholder="Nome">
<input type="text" name="email" placeholder="E-mail">
<input type="password" name="password" placeholder="Password">
<input type="password" name="conf_password" placeholder="Confirmar Password">
<input type="submit" id="envia_dados" name="enviar" value="Registar">
</div>
</div>
</form>

#form_login{
width:600px;
height:300px;
margin:auto;
margin-top:100px;
}


/*::::Posiçao da imagem user::::*/
#user{
background-image: url(img/user.png);
background-repeat:no-repeat;
width:256px;
height:256px;
float:left;
}


/*::::Posição do formulario Registo::::*/
#formulario_registo{
margin:10px 300px 20px;
}

Como faco para a imagem ficar com funcao de file?

*Mas quero remover o button e o texto.

Obrigado a todos

[I-NOZex]

http://ericbidelman.tumblr.com/post/14636214755/making-file-inputs-a-pleasure-to-look-at

http://stackoverflow.com/questions/5813344/how-to-customize-input-type-file

http://css-tricks.com/snippets/css/custom-file-input-styling-webkitblink/