Basically its a LCD panel...you would need to buy a separate controller in order to drive the display since the controller included in the photo frame more then likely wouldnt be able to accept a VGA signal.
Additionally you would need to find a compatible cable to connect the panel to the controller. If you are proficient in electrical engineering you can get the data sheet for the LCD panel and design your own cable...
My opinion is it wouldnt be worth it since the availability of LCD controllers to the consumer market is very limited, and if you were able to find a compatible one the cost wouldnt justify using the photo frame in the first place...There are open frame monitors already on the market..
Here is a link to a VGA controller:
http://store.earthlcd.com/NK-GM2221-...=7&category=99
And a LCD kit:
http://store.earthlcd.com/SK-1009T-S...7&category=255