Perdendo GraphicImage após refresh na página

public void mostraFoto() throws IOException {
	FacesContext facesContext = FacesContext.getCurrentInstance();
	ServletContext scontext = (ServletContext) facesContext.getExternalContext().getContext();

	if (objeto.getId() != null) 
	{

		File file = new File((pastaFoto + "/" + fotoCurriculo.getFoto()));
		// efetura a leitura

		try {

			BufferedInputStream in = new BufferedInputStream(new FileInputStream(file));
			byte[] bytes = new byte[in.available()];
			in.read(bytes);
			in.close();
			//isto abaixo é um teste
			dsc = new DefaultStreamedContent(new ByteArrayInputStream(bytes)); 
			//dsc = new DefaultStreamedContent(new ByteArrayInputStream(bytes));

		} catch (Exception e) {
			FacesContext context = FacesContext.getCurrentInstance();
			System.out.println(e);
			/*
			 * context.addMessage(null, new
			 * FacesMessage(FacesMessage.SEVERITY_ERROR, "Erro! " + e
			 * +", "));
			 */
		}
	}