E-Shop system

Hi, i'm currently analyzing an e-shop system. i understand how to display products and so on, however i still have some question marks on the following topics: 1. what is the best way for showing product image ? - to store them in DB or onto filesystem as simple image files ? - each product should have 2 images (1 small when user browser the catalogue, 1 huge (standard) when user wants to see how product looks like). Should be 1 or 2 images ? I mean should i store in DB/filesystem the standard file and reduce size for user browsing ? 2. billing interaction basically i was thinking to allow users to pay via PayPal, Bank2Bank and by credit card. - What i do not understand is how can i interact with such third party company ? - for paypal: how can i redirect user to PayPal and pay to my account and how to get back information that he paid (and that i can send the good) ? - Bank transfer: how can i control it ? - Credit card payment: how can i be sure that when user give me his credit card number, my application will secure it enough ? how can i get back information that it's true...user paid the good and i can send him the product ? thanks a lot for all your feedback. -- Alain ------------------------------------ Windows XP SP2 PostgreSQL 8.2.4 / MS SQL server 2005 Apache 2.2.4 PHP 5.2.4 C# 2005-2008