Erro ao exibir imagem no primefaces - RESOLVIDO

			File f = new File(al.getAluno_foto());
			if (f.exists()) {
				InputStream stream = null;
				try {
					stream = new FileInputStream(f);
					imagem = new DefaultStreamedContent(stream, "image/jpeg");
					setImagem(imagem);
					
					
				} catch (Exception e) {
					e.printStackTrace();
				}
			}

			<p:dataGrid var="lst" value="#{consalunosBean.lstAlunos}"
				columns="3" rows="6" paginator="true"
				paginatorTemplate="       "
				rowsPerPageTemplate="9,12,15" id="gridPesqAluno">

				<p:panel header="#{lst.nomeAluno}" style="text-align:center">
					<h:panelGrid columns="1" style="width:100%">
						<p:graphicImage value="#{lst.imagem}" height="150px"
							width="150px" />
						
						<h:outputText value="#{lst.serie}" />

						<p:commandLink update=":form:carDetail"
							oncomplete="carDialog.show()" title="View Detail">
							<h:outputText styleClass="ui-icon ui-icon-search"
								style="margin:0 auto;" />
							<f:setPropertyActionListener value="#"
								target="#{consalunosBean.alunoSelecao}" />
						</p:commandLink>
					</h:panelGrid>
				</p:panel>
			</p:dataGrid>

  <mime-mapping> 
   <extension>jpg</extension> 
   <mime-type>image/jpeg</mime-type> 
  </mime-mapping>