Adding missing preview images.

Author: BackTrak

com.zaphop.visualizer.csproj

@@ -187,7 +187,9 @@
       <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
     </Content>
     <Content Include="LICENSE.txt" />
-    <Content Include="previews\Preview.png" />
+    <Content Include="previews\Preview.png">
+      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+    </Content>
     <Content Include="PropertyInspector\PluginActionPI.html">
       <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
     </Content>