Optimize Website hosted on VPS running on Prestashop 1.4.4.1

Hello Domain : [login to view URL] ecommerce : Prestashop 1.4.4.1 Hosting : vps, virtual dedicated server 1. Overloading the server's memory and CPU : Troubleshoot & Fix it 2. Images : Upload imgs in right location / See images in the Back end / Access images from Back end via .jpg link 3. Site speed : Decrease site loading time , without overloading the server (cache) (Note : current cache is deleting files that were unused for 48 hours) This project is about , someone experienced with prestashop which knows which line of code to update so that it'll change the way the website is behaving, and the time it takes to load pages . Thank you, Happy bidding :)