Magento Product Import Product

I need a php script to run on my server with magento. At end of each day a will export a xml from my store and import with this script to my online store, if i have new products i will ftp the images Every time i run this script, it will take all products from a xml - you need to send me this xml template - and update my products database. - If a product exist, update all informations and stock. - If a product don't exist, create this. How we can work with products image import? ftp is the best solution? Thanks