图片控件picture控件的进一步封装： 在支持右键弹出菜单的基础上，又增强功能， 支持控件自己重绘，这样显示的图片父窗口就不用重绘了。-Picture control picture control further package: in support of the right based on the pop-up menu, and enhancements to support the control to redraw their own, so the picture sh