Settings for Windows 10.
Settings for Windows 10.
We're curious if we can create this on the mini preview (image 2). Did you accidentally trigger a list mode by clicking something?
Are there several Explorer windows active at once, or is it just a single window? You'll see the list only when an app opens enough windows to display the taskbar icons stacked.
Registry modifications or Group Policy changes? Check the Windows 10 guide on thumbnail preview settings.