如何创建全局的System::Drawing::Image？

我想把一个png读进来放在一个固定的Image全局变量里，试了各种方法都不行。
好像是托管什么的问题。
本人刚从bcb转到C++.net，非常不适应……
求各位牛人指导

ref class yourclass
{
static image img;
....

ref class Form2
{
static Image img;
};

编译不通过啊
1>d:\it_projects\vc\lab\trydraw\a\a\dxdraw.h(34): error C3622: 'System::Drawing::Image': a class declared as 'abstract' cannot be instantiated
1> c:\program files\reference assemblies\microsoft\framework\.netframework\v4.0\system.drawing.dll : see declaration of 'System::Drawing::Image'
1>d:\it_projects\vc\lab\trydraw\a\a\dxdraw.h(34): error C3622: 'System::Drawing::Image': a class declared as 'abstract' cannot be instantiated
1> c:\program files\reference assemblies\microsoft\framework\.netframework\v4.0\system.drawing.dll : see declaration of 'System::Drawing::Image'
1>d:\it_projects\vc\lab\trydraw\a\a\dxdraw.h(34): error C3162: 'System::Drawing::Image' : a reference type which has a destructor cannot be used as the type of static data member 'Form2::img'
1>dxdraw.cpp(103): error C2660: 'loadimg' : function does not take 0 arguments