I am a newbie here. I do want to offer some help. But I am not a long-term worker dealing with the document and image conversion work. As for myself, I used to do the
conversion work with the help of some fine 3rd party conversion SDKs according to its tutorials about
how to convert document using C#.NET. I have only tested its free trial package, it worked well for me. It is one of many, but I do appreciate it so much because it is manual. Share with you, and I hope you success. Good luck.