Dat grain
Dat jaypeg
'Should raise your render samples to at least 256 for both depth of field and motion blur, even if you have a still shot that doesn't use DOF, raising the samples will anti alias the image and smooth out the ambient occlusion
And make sure to render your picture as a TGA so you keep the picture perfect quality, and then use whatever image editing program you have to save it as a PNG or JPEG, programs like Paint.NET and Photoshop can edit Targa images