Construct 3 does not natively support sprite mesh deformation. I don't know if there are any third party plugins for it.
I would look for a dedicated imaging program for this type of image manipulation. I believe Spine is a well known one, and Spriter 2 (not yet released) plans to support mesh deformation.
I see, so this is a limitation of C3.
I'm looking for a way for my users (who will use my software) to have more control, but I guess it's not possible with the built-in tools at the moment.
Although I'm on the fence for third party editors since we now have timelines.
I thought the timeline is for animating over time, not deforming shapes, but I may be confused after all I'm still a noob, I have much more to learn. :)