MS Word Icons: Auto changed visual look

[Colonel Conundrum]

Hello friends,



My first time using a forum so hope I have followed protocol.

Just got off the phone with Dell Premium support and I stumped them. Yesterday my Word icons suddenly changed from the generic look to showing a preview of the 1st page of the document's contents. I've uploaded a photo of one generic-looking icon and one with the preview look. Does anyone know what happened and how to revert from preview back to generic?

There was another issue that Dell was able to fix. When I was saving a newer version of the document it stopped giving me the ability to save as the new version and kept creating a newer, additional file. Like I said, Dell fixed that; mentioning it in case it provides add'l context.

Win10, 64 bit
Word: Version from Office 365

Thank you :-)

[Moonshine]

It looks like the Save Thumbnail option has been used under the File name/Save as type options: