Though I haven't done what you're attempting myself, it shouldn't be too difficult to add a new generic_content provider. remember you can have a different provider for each type of content, like "Employees" and "Products" etc, with each having its own section that you can admin separately underneath the generic content module.
You can set separate meta fields for your "Employees" provider to just collect the data you need, including a thumbnail url. on the front end, when you drop a contentview on the page, you can select the "Employees" provider (instead of the default one) and futher filter by category, tag, or anything else you need from the advanced tab of the properties for the control...
However, I needed a similar list, just employees, phone numbers, no picture. I ended up just making an intrasite module, linked to my sql table using a dataadapter and dataset.
Sitefinity is flexible to allow you to do either approach, whichever you feel more comfortable with. The generic_content route is simpler, but the custom intrasite module is eertainly more flexible (but takes longer).
hope this was helpful let me know which approach you think would work best for you and I'll do my best to help you on your way!