CorelDRAW / DESIGNER SDK :: How To Programmatically Lock Ratio Of Scaling And Sizing Of Image Imported On Curve

I am a  C# developer and  not  very familiar with coreldraw(when using with c#). My problem is that i am programmatically importing image on a curve using the following C# code.

d.ActiveLayer.Import(imgpath);// image path is path of the cdr file

                                            var v = d.ActiveShape;
                                            v.SizeHeight = 20.00;
                                            v.SizeWidth = 15.00;
                                            v.AddToPowerClip(s);

Now when i run this code the image gets placed into the curve bit it gets stretched vertically means the face of  a student(that comes from imagepath) get stretched  vertically..When i do this Manually with scaling and sizing ratio locked it gets properly inserted in curve....