(Information and examples taken from the DroidScript documentation)

The SendMail method allows you to send emails via any of the email Apps found on your device.

You can also specify an optional attachment file. Leave out the last parameter or set it null if no attachment is required.

 app.SendMail( address, subject, body, attachment );

function OnStart()
{
   var file = "/sdcard/MyPic.jpg";
   app.SendMail( "myfriend@gmail.com", "MySubject", "Hello", file );
}