Sorry this post became more of a modx sales pitch then answering the questions.
I use foxycart. I like that the checkout can look exactly like your site and that they handle all the security. I do not have any inventory tracking or order tracking in the site manager my clients track that through there email, It's actually more natural for them.
As for resizing the images here is the exact code I use. phpthumbof is available in the package downloads. The onerror is an Output Filter, these are very powerful. If an images is not available it is replaced with a defualt image, I do tell my clients not to use large file images. There are a number of ways for them to be batch resized. (see:
http://rtfm.modx.com/display/revolution20/Input+and+Output+Filters+%28Output+Modifiers%29)
<img src="[[*image:phpthumbof=`w=200`]]" onerror="this.src = '/product-images/coming-soon.jpg'" alt="[[+pagetitle]]" />
I use 5 templates for the site:
a base template- this is only the framework design used on basic info pages.
a home page template-this allows me to customize sections my client can input specials and such into.
a product detail template - this uses a verity of TVs to create a product detail page. I can also use the importx package to upload products from a cvs. The one site has almost 800 products so far.
a product sub category template- This use the getResources package to pull info from the resource's TVs to create a menu of categories.
a product minishop - This uses the getResources package to displays a mini versions of each product using the info in the TVs. It can be ordered right from there or clicked to view the details page.
a checkout page - customizes foxy cart to match the rest of the site,
I use the Packman package to to make a nice ecommerce package that I can install in a new site and start to customize.
I continue to tweak the package as I learn new things.
One thing I did try to do was use the new articles package as a category for the products. I ran into too many issues and haven't quit figured it out. When I do I think it would be great. I should get with the author to solve them. Haven't had time.
I think that's the first time I ever wrote out my process. Hope it helps.
[ed. note: crecorn last edited this post 12 years ago.]