Try using a hidden attachment as per .net - embedding attached image in html email
Dim plainView As AlternateView = AlternateView.CreateAlternateViewFromString("This is my plain text content, viewable by those clients that don't support html", Nothing, "text/plain")
Dim logo As New LinkedResource(Server.MapPath("images1/links/beach-icon.jpg"))
logo.ContentId = "embeddedimage"
Dim htmlView As AlternateView = AlternateView.CreateAlternateViewFromString("<p>Here is an embedded image.</p> <img src=cid:embeddedimage> <p>More text here</p>", Nothing, "text/html")
htmlView.LinkedResources.Add(logo)
objMM.AlternateViews.Add(plainView)
objMM.AlternateViews.Add(htmlView)