add robots picture to welcome index page

app/views/welcome/index.html.erb

@@ -32,8 +32,8 @@
 		<div class="weixin-content">微信扫码</div>
 	</div> 
 	<div class="main-content-bar" id="main-content-bar">
-		<div style="float: left">
-			<%= image_tag '/images/transparent.png', size: "75x75" %>
+		<div style="float: left; padding-left: 15px;">
+			<%= image_tag '/images/welcome/rosNetworkingCrop.png', size: "107x63" %>
 		</div>		
 	<div class="welcome_left" id="welcome_left">
 		<span class="" style="font-weight: bold; font-size: 18px; color: #e8770d;display: inline-block; margin-top: 5px;">