Not sure if I understand the question or not.

You want to show  an email  image in the web part? Or show (email) after the title? Maybe with a link to sending the thread  via email?

You might be able to add an image  by converting the web part to a DataView Web part, but there’s so much DHTML in there for collapsing and expanding the thread, it would probably be messy.

If a small email  image will be messy just before the title of every thread, is this possible.

Right now the situation is users doesn't know that email this thread  option is available unless they click on the context  menu. It's kinda hidden right now. So just after the subject/title of the thread completes, can we add a text  saying (Email) For example.

This is a new thread (Email)

Now user  will try to click this email, which is just a text not a hyperlink and it will open up the context menu.

Where do I need to modify to add (Email) in ows.js file.

Still not sure what you’re asking but here goes.

The team site template you see is available as a download from MS and has some enhancements. The menu  is one of them as it adds a new menu item “Send Email for Review” by adding this javascript to the list:

<script language="javascript">

function Custom_AddListMenuItems(m, ctx)
{
var strDisplayText = "Send Email Link For Review";
var strAction;
var strImagePath = "";
// parse the URL out of the itemTable
var URL = "";
var index = itemTable.innerHTML.indexOf("href=");
if (index > 0)
{
var str = itemTable.innerHTML.substr(index + 6);
index = str.indexOf('"');
if (index > 0)
{
URL = str.substr(0, index);
}
}
if (URL != "")
{
strAction = 'window.navigate("mailto:%20?subject=Please review...&body=%0A%0A%0A<' + URL + '>")';
// Add menu item
CAMOpt(m, strDisplayText, strAction, strImagePath);
// add a separator to the menu
CAMSep(m);
}
return false;
}

</script>

You could certainly add that to a Content Editor Web Part and drop it onto a page with a normal discussion  board.

I personally wouldn’t add “Send Email” to every thread  as it would just look crazy trying to read the threads. Instead you could direct people to use the menu item that you add (with the javascript above) and tell them to use that if they want to send a link. You can’t really create this as a single link as it’s dependent on the context  of the thread so that’s why it’s added as a menu option.