I am wondering what kind of controller board I will need to get in order to use to use an LCD screen that has been "abandoned" by its motherboard. It still has the VGA cable and backlight inverter attached. Is it possible to find a board that has a USB port that when I put a flash drive in with pictures it will display them?
I found controller panels like this but I don't know if it will help me do what I am looking to do.
Provided you can read that wall-o-text and figure out if your LCD is supported - maybe? Another supplier is Earth LCD (http://store.earthlcd.com/); they might be able to help you find something. I doubt, though, that you'll find anything to turn it directly into a picture frame, at least not without paying waaaaay more than a comparable size frame would cost new.
Generally, the cable running from a laptop LCD is not VGA, but a digital connection more akin to DVI. The circuitry to convert the video signal to the format used by the LCD exists on the mainboard, and cannot be physically removed. This would require signficantly more effort than simply mapping pins to a VGA connector.