Its not just a picture, and its not comparable to a baby in a bath. Child pornography is video and images of people ages 0 to 17 - most being toddler and pre pubescent- being vaginally, anally raped or being forced to perform orally on grown men. 
The act of consuming such violence against babies and children fuels the production of the product, which requires children to be sexually abused by adults, and recorded and distributed. So, if you are sending grandmama photos of you anally raping your children, or vaginally penetrating your daughter in the bath then yes I suggest you delete those.