Forget the WebBrowser control for this kind of application. You dont need to automate the browser, or any plugin. In the background there is always http traffic. You should familiarize with
http protocol[
^] concepts, and than trace the actual conversation between your browser and the application on the server. You can use tools like
Fiddler[
^]. You will find a series of GET and POST (or other verbs) requests from client side. You can figure out how data entered by you is sent to the server, what url is called, what fields are populated. You can simply send (upload) images also. You can use the
HttpClient[
^] class for that. Keep in mind, that you don't have to automate the browser, you have to simulate the browser and the user actions on a lower level. If you do it right the server will see no difference. It is really not complicated.