Add extra info for upload (OrcaCollective#111)

OpenOversight/app/templates/submit_image.html

@@ -35,9 +35,13 @@ <h3>Select the department that the police officer in your image belongs to:</h3>
 
    <h3>Drop images here to submit photos of officers:</h3>
 
-   <form id="my-cop-dropzone" action="/upload/department/1" class='dropzone'>
-   </form>
-   <p>Drag photographs from your computer directly into the box above or click the box to launch a finder window. If you are on mobile, you can click the box above to select pictures from your photo library or camera roll.</p>
+    <form id="my-cop-dropzone" action="/upload/department/1" class='dropzone'>
+    </form>
+    <p>
+      Drag photographs from your computer directly into the box above or click the box to launch a finder window.
+      If you are on mobile, you can click the box above to select pictures from your photo library or camera roll.
+      An image is successfully uploaded when you see a check mark over it.
+    </p>
 
     <script src="{{ url_for('static', filename='js/jquery.min.js') }}"></script>
     <script src="{{ url_for('static', filename='js/dropzone.js') }}"></script>