Add a few new products to my page and troubleshoot how I am suppose to do it

Hello I have about 4 new products I need added to my merchandise page on my site and i need a few category images changed no more than a 3 images there... that's pretty much all I need done right now I would do this myself but our previous coder (*LIKE MOST) vanished and has yet to tell us how to add the products or new products cause it looks like he used some database or some sort of php function on the page... so hopefully you will be able to help us do this cause he said images AUTO SIZE the way he made it where he added them, so I know he isnt just adding them into a page... so i need someone to help me figure this out because it is very important not to mess up any of the page layout structure or size of the page and such as everything is finally looking perfect like we need and want. so please only bid if you can help me trouble shoot this and get my new images on there and keep everything working properly...