System.Drawing is not in add reference
<p>To write a Winphone app, I need to use using System.Drawing, and I found on Internet I should first add reference, it is not in the .NET list, what should I do?</p>

<p>It is Visual studio 2010.</p>

<p>In one solution, it says .NET 4.0 and above supports this, where should I check the version information?</p>

<p>Thanks</p>
