It is good to know that you have been able to extract the Word file from OLE. You can work on that file and save that a Word file. Then you load the OLE file using stream and don’t forget to set the position of loaded stream to 0. The convert the stream to byte array and set that as OLE data. I hope this will work. If you find any issue then please share a working scenario (sample project) that we may use to reproduce issue on our end and help you.
I suggest you to please try using following sample code to add image to Ole frame. The oof is OleObjectFrame object.
Bitmap imgChart = "Any Bitmap"; oof.SubstitutePictureFormat.Picture.Image = pres.Images.AddImage(imgChart);