Now you’ll need to select a compression setting to save your movie. The default is “best quality for playback on my computer,” which is a WMV file, 640x480 pixels. You’ll notice that’s twice the dimensions of the file that gets saved in the Send to the Web option.
However, for optimum upload, you’ll probably want to select “Show more choices” and then select “Video for Broadband (340 kbps)” from the drop-down menu. This will save your video with the optimum settings for upload to a video sharing website.