Saving Image(Or a video) Processed using Pixel Shader

Hii,

I have created a small effect using pixel shader and applied it to a image usingWPF in c#.Everything works fine but now i am stuck with this final step.How to actually save the image ,after pixel shader effect is applied?? 

For E.g., I have applied a grayscale effect to a image in image control.Now I want to save it in some format, say jpeg. How to do it? moving further, I want to apply the same effect to a video also. I can manage to apply it but finally how to save that? Please some experts out there help me!!

Again I used WPF in c#... Thank you in advance!!

vignesh