Hi Hamid,
Its possible to connect CMOS camera to FPGA.
The problem in hand is not connecting a camera to FPGA, but rather connecting internal memory of the camera to FPGA through RJ45 protocol.
So, I would like to suggest a few steps for design
1. Check what type of memory is in Camera, (FLASH, SDCARD etc).
2. Get its spec.
3. Understand the RJ45 protocol.
4. Check out how the memory opertations are supported in RJ45 protocol.
5. Understand the how to detecte the Camera using RJ45.
Hope this give ample idea about your problem
GCK