Image trace (for fill coloring) distorts image

I need to fill the white background of a colored-pencil drawing.  I did image trace to allow this (if there is a better option, I'm all ears).  Every image trace setting, though, always distorts the image and makes it a bit more blurry (almost like water colors).  See picture below (left is distorted, right original).  Any suggestions?  I'm still fairly new to Illustrator but didn't have this issue with the last kids book I made.

Thank you!