>Can the map service, write its output to a directory (Say it "output") which is parallel to WEB-INF ?
Yes.
Will that (output dir) be not writable?
That depends upon the server setup. You need to grant permissions so that your server can write to that directory.
You could also just send the requested image to the client without saving it to disk.
Either way, to load an image onto the page, you use the <img> tag as normal in HTML.
<img src="<%= imageFileName %>">
or
<img src="ImageServlet?imageid=42">
Using a
Servlet to send the image back via an output stream is a good option.
Cheers,
evnafets