Finally i solved the issue.used below code to addpicture
tempSlide.Shapes.AddPicture(strImagePath, Microsoft.Office.Core.MsoTriState.msoTrue, Microsoft.Office.Core.MsoTriState.msoFalse, Convert.ToInt32(shape.Left), Convert.ToInt32(shape.Top), Convert.ToInt32(xmlTempNode.Attributes["imgwidth"].Value), Convert.ToInt32(xmlTempNode.Attributes["imgheight"].Value));//load new image to shape
The problem was, i was sending msoFalse for LinkToFile and msoTrue for SaveWithDocument.
and now ,passing msoTrue for LinkToFile and msoFalse for SaveWithDocument did my job.
happy Coding..