Custom picture uploader tool

I need a custom picture upload tool that will work similar to the way ebay's does. I have custom templates that I use for auctions and they can hold up to 10 pictures. I need a tool that will allow the people who do listings for me to simply click on the image placeholder in the template and have a window come up that will: - allow them to select a picture anywhere that it may be stored - automatically resize the picture into 2 sizes - a large one 500 pixels wide and a small one 100 pixels wide (or as close as possible to these figures while keeping the original proportions intact) - and enter the appropriate code for their display. Here is a sample of one of the picture display codes: <img src="http://www.123softsales.com/auctions/dim2400sml2.jpg" alt="Item Photo" title="Item Photo" onClick="document.swap.src='[login to view URL]';" width="52" height="123"> - automatically upload both pictures to the appropriate folder on our servers. The people who do listings for us do not have much html experience at all, so I need this picture uploader tool to be as much of a "point and shoot" type application as possible.