so it means that the input voltage needed by the arduino and ethernet shield is from 7v - 12v...
Yes.
it is possible that the data coming from c328 camera would flow in ethernet shield of arduino?
It is? Is it possible for that camera to deliver data slow enough for the Arduino to read it and send the data via the Ethernet shield someplace? In order to send picture data, you'll need to define, up front, how large the picture data is. Can you do that without reading all the picture data?