How do you automatically separate Camera photos from Safari photos?
As answered before, you cannot do that from the Camera app or Safari. But a workaround could be to use another camera-app ie "Camera+" which costs 1 or 2$. 

Download Camera+, choose Menu, choose Autosave, choose Lightbox (Camera+'s own cameraroll). 
Then you save new pics to Lightbox - and you must export them from that of cos.