vaadin portlet for liferay: Uploading a png and showing it take too long

Hi every one,
I made a vaadin portlet and deploy it to liferay. The user can add a new item when he click the add button a new form is showing and the user have to enter information related to the item he can also upload a png and a jrxml design. My app will show the uploaded png in an embedded component and process the jrxml to transform it into a png, save it to a folder in the system then show it in an embedded component. Every thing work fine when i deploy in tomcat but when i deploy in liferay the images take too long to be shown what could be the problem here is my code to show an image after the upload succed event :

formHeader.getImageUploader().addListener(new SucceededListener() {

			public void uploadSucceeded(SucceededEvent event) {
				if (event.getMIMEType().equals("image/png")) {
				} else {
							"Not a supported File!!",

Here is the code of the setProductImage method

public void setProductImage(String productImageName) {

private FileResource getProductFileResources(String fileName) {
		File file = null;
		FileResource res = null;
		file = new File(MYApplication.getProperties().getProperty("imagesfolder") + fileName);
		res = new FileResource(file, getApplication());
		return res;

productImageField is an Embedded component

please help me im pressed by time thanks in advance