.NET C# updates to existing CMS

I have a custom built CMS that user's can log in, add/delete PDF documents, the filenames get stored in a DB. The CMS can then get queried via a URL to output an XML list of the filenames.

When uploading a PDF the user currently also gets the option to upload an image that will act as a thumbnail. We now want to change this so the thumbnailis automatically created when uploading the PDF.

It looks like it is possible to do this via ImageMagik (but using .NET version https://magick.codeplex.com/)

Extra notes:
Source code must be sent after project completion.
No screenshots of the app can be posted online.
NDA must be signed before project commencement