Convert to line drawing

I have come across an issue with the completed Video Scribes. As we decided to hand draw our pictures once we upload them to the canvas the hand that draws them will repeatedly draw around the pictures instead of just the once. When you originally upload the pictures you are required to select 'Convert to line drawing' and the only format that works in the bottom left option. Every other option does not work properly. I don't suppose you have any suggestions to fixing this issues? I have tried speeding up the pictures  and using  a tablet to draw, but it still has the same problem and draws the picture repeatedly.

If you could help that would be fantastic,

Thanks.