WPF图像不会显示位mapsource

I'm new to using WPF and GDI, and I'm having trouble displaying an image. My eventual goal is to build something expose-like. So far, I gray-out the screens, gather all the active HWNDs, and capture the screens of all the windows. For now, I have a single Image element that I try to set the source for, but nothing ever shows up.I'm new to using WPF and GDI, and I'm having tr