I'm writing a flash app using the open source tools. I would like to load a data file in to the app and capture a screenshot of the stage on the server. The only part that seems mysterious is running the app on the server. In fact, I don't even care if it's the same app running on the server and in the browser--if I can use the flash stage and drawing routines to produce an image server-side, I'm happy. If I have to delve in to flex, fine. Right now I'm having problems finding any starting point at all.

I gather Adobe has some commercial products that may fit the bill, but I'd like to stick with open source, apache, and linux. I know this is probably possible with haxe/neko, but I'd like to use more mainstream tools if possible. Am I asking too much?

EDIT/CLARIFICATION: Many thanks for the responses so far, but I think I've been a bit muddy in my description. I've already written the actual stage-grabbing stuff using the same PNGEncoder class as was suggested. The problem is in actually running the swf on the server side. I don't want to let the client take the screen shot itself, because this opens up the possibility of the client maliciously submitting a screenshot which does not correspond to what is on the stage, that is, I don't want users uploading porn. If I could run the the actionscript code on the server, then I could generate the screenshot from my data files and be sure that the screenshot matches the data, but I have no idea how to run the actionscript or swf on the server.