This is not directly possible with <h:graphicImage>. It can only point to an URL, not to a byte[] nor InputStream. Basically, you need to make sure that those bytes are directly available as a HTTP response on the given URL, which you can then use in <h:graphicImage> (or even plain HTML <img>).
Provided that you’re identifying the image by its ID like so:
<h:graphicImage value="/image/#{someBean.imageId}" />
Here’s a kickoff example of such a servlet:
@WebServlet("/image/*")
public class ImageServlet extends HttpServlet {
@EJB
private ImageService service;
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
Long id = Long.valueOf(request.getPathInfo().substring(1));
Image image = service.find(id);
response.setContentType(getServletContext().getMimeType(image.getName()));
response.setContentLength(image.getBytes().length);
response.getOutputStream().write(image.getBytes());
}
}
A more advanced abstract template for a static resource servlet, supporting HTTP caching, can be found in this answer, along with a concrete example for serving from database.
If you happen to use JSF utility library OmniFaces on a JSF 2.2 + CDI environment, then you can instead use its <o:graphicImage> which can be used much more intuitively.
<o:graphicImage value="#{imageBean.getBytes(someBean.imageId)}" />
@Named
@ApplicationScoped
public class ImageBean {
@EJB
private ImageService service;
public byte[] getBytes(Long imageId) {
return service.getImageBytes(imageId);
}
}