You can choose what size your meeting participants are displayed in the video windows of the VIA3 meeting window by selecting View>Video Size from the meeting window menu.
Video Size allows you to adjust the size of the video windows that appear in your VIA3 Meeting Window. You may select from:
50% (Half)
100% (Small)
150% (Medium)
200% (Large)
Auto Size, which automatically resizes the video windows relative to the width of your VIA3 Meeting Window.