Accessing related entity of an entity stored in HttpSession - jpa

Question

I have an image upload/store application in which I have a User entity having multiple related images(List<Image> images using OneToMany relationship). I am iterating images of the user in session using struts iterator tag in Home.jsp
<s:iterator value="#session['user'].images" status="itStatus">
<s:property value="imageid"/>
<s:property value="name"/>
<s:url action="GetImageAction" var="imgUrl">
<s:param name="imageId" value="imageid"></s:param>
</s:url>
<li>
<img src="<s:property value="#imgUrl"/>"/>
</li>
</s:iterator>
The upload form is on the same page so when the user logs in, he can see the images he has already uploaded & can also upload new images.
Here is my problem. When a new image is uploaded, the same page refreshes to show his images but the recently uploaded image does not get displayed(appears as broken) but I am able to see all previously uploaded images. This is because the imageId field of Image is having the value 0 in this case instead of the correct id. GetImageAction action sets the inputstream from the image using the param imageId
Here is the Image class:
#Entity(name="Images")
public class Image implements Serializable {
private long imageid;
private String name;
private byte[] image;
private static final long serialVersionUID = 1L;
public Image() {
super();
}
public Image(String name, byte[] image) {
super();
this.name = name;
this.image = image;
}
#Id
#GeneratedValue
#Column(name="Id")
public long getImageid() {
return this.imageid;
}
public void setImageid(long id) {
this.imageid = id;
}
...
}
Now I am guessing this is because the new Image object iterated is having the default long value 0 instead of the generated Id (I am able to access other fields' values like name). Why is this? Since the image is already persisted by the time the result is displayed, shouldn't the Id value be retrieved correctly? What am I doing wrong here?
Please help. I feel I may be missing something simple here but it just wouldn't get solved.
Edit:
UserAddImageAction
public class UserAddImageAction implements SessionAware {
private User user;
private Map session;
private File photo;
private String photoContentType;
private String photoFileName;
public String execute() {
EntityManagerFactory emf = Persistence.createEntityManagerFactory("StrTest1");
EntityManager em = emf.createEntityManager();
EntityTransaction etx = em.getTransaction();
try {
BufferedInputStream i = new BufferedInputStream(new FileInputStream(photo));
ByteArrayOutputStream baos = new ByteArrayOutputStream();
int c;
while((c=i.read()) != -1) {
baos.write(c);
}
user = (User) session.get("user");
user.getImages().add(new Image(photoFileName, baos.toByteArray()));
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
etx.begin();
em.merge(user);
etx.commit();
em.close();
emf.close();
session.put("user", user);
return "SUCCESS";
}
...