Hi @nazareth k thanks for posting in the community! It sounds like our Embeded links may be helpful for your use-case. If your PowerPoint or Excel files are from Microsoft OneDrive you can embed the links into Lucid. These embedded links will allow you to refresh the content from within lucid toggle through to select a new thumbnail and extract a thumbnail to use as an image on the canvas.

For more information please visit our Embed links and media in Lucid article from the Help Center. 

Please let me know if this is not what you are looking for or if you have any additional questions. Hope this helps!