If DVD Authoring in Elements is similar to authoring with Encore, then the transcoding settings are probably set for automatic. Basically, Elements calculates the highest possible bitrate that will allow the content to fit on the disc. Still image menus use almost no disc space (Kilobytes) while menus with video backgrounds will use more. While you could try to set your transode setting manually, you may end up with a file that is too big to fit on the disc. You may want to check the settings to ensure the quality setting is max’d. I’m not sure what impact this setting will have on file size but I always have it set to its highest (when possible). Also, see if you can do a "2-pass" transcode. That might also help.
