Hello,
I think you should consider to buy a Raspberry Pi. Because it will make your work way more easier. I believe you will need to buy more Arduino components for running your system smoothly. Especially for displaying saved images on your LCD. So, if we consider the money that you will spend on extra components and consultation for wiring it, Raspberry Pi can be cheaper option. Also, if you buy a Raspberry Pi, you can easily find videos on internet about CCTVs and other camera stuff therefore you can build the system yourself. I even can provide some links.
I know, you don't need suggestions, you need work with your current components but unless freelancers are successful with current components you should keep Raspberry Pi option in your mind.
I don't want any money. Just wanted to help if I can.
Sincerely,
Emre