My taskbar only shows names above the icons.

Hi, you could use this excellent free tweaker (with full explanations) and uncheck this to enable thumbnails:


Or you could search the huge searchable Tutorials section and maybe you would find this:
Enable or Disable Thumbnail Previews in File Explorer in Windows 10

I think you will find they do the same.. the first is much more convenient.

Thanks. It works on a normally functioning system. It appears yours is not, alas.

Please answer the following carefully and in order.

Please post a screenshot like mine to show current status of that setting.
Confirm you received a UAC prompt when launching WinAero's tweaker.
Confirm that when you changed the option you did (as prompted) restart file explorer or restart your PC.
When enabled, the checkbox should be clear.

Still problems? Then - standard basic diagnostics:

Please create a completely new user account purely for test purposes.
Log in as that user- do you see the same thing?

This is important as if you do not, the problem is specific to your user accont.
If you do, then either there's a problem with your Windows installation or the same 3rd party program (e.g.) is interfering.

If you do, please try a clean boot (Google or see tutorial if unsure how).
Do you see the same problem?

This has been bothering me for weeks and I have not yet found any solution.

When you first noticed this did you try using a System Restore point or restoring a disk image? (I hope you are using 3rd party disk imaging regularly and routinely).

History:
Noting thattaskbar thumbnails are not shown in Safe Mode, did you disable any services or tweak Windows or install any programs around the time this started?