Syncing to launchbox does NOT upload anything to the database.
I've been working on a lot of apple ii stuff. What has been working for me is to work on your local database. Download images, create videos, etc and place them in your local folder.
Then use use the "add games to DB" plugin, found here:
with the plugin installed, you then right click on the game of interest. Towards the bottom of the context menu, you'll see "add game to database" or something like that.
For videos, I've been using snagit. If no video is present, I don't think anyone cares how long the videos are. We're a long way towards demanding a certain bit rate, resolution, time, etc.