Hi There! We do already have a feature that allows you to add draw paths for your custom images, please watch our tutorial #8 to help you get started: https://www.doodly.com/tutorials/
What I mean is when we import our own images, those typically taken by our cameras, can be converted to a sketch-like doodle. I hope you can consider this again. If only I can provide images here in this request as an example.
When I want to convert my photos into sketch-like drawing, I have to use Photoshop.