How to disable Taskbar Thumbnail preview in Windows 8 ?

On Windows 8.1 you can get rid of it with these settings:

Windows Registry Editor Version 5.00

[HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Taskband]
"NumThumbnails"=dword:00000000

[HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced]
"ExtendedUIHoverTime"=dword:41fffffe

Import them and restart Explorer. See here.

A few options (I've only tested option 4):

Option 1: (I haven't tested this one)

1. Click on Start button and type RegEdit in Instant Search text box, then hit Enter.

2. In the Registry Editor, navigate to the following registry key: HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer

   Note: If Explorer registry sub-key does not exist, then right click on Policies and click New -> Key and name it as “Explorer”.

3. In the right pane, right click and select New -> DWORD (32-bit) Value.

4. Type TaskbarNoThumbnail as the name for the new registry value data.

5. Double click on TaskbarNoThumbnail to modify its value data.

6. Type 1 and click on OK.

7. Restart computer if needed.

   To re-enable Taskbar thumbnails again, just right click on TaskbarNoThumbnail and click Delete to remove the whole registry key, or set TaskbarNoThumbnail value data to 0.

Option 2 and 3:

Install 7+ Taskbar Tweaker 4.5 - This does work on Win 8.1

In the Hovering section, check the box 'nothing'

Install Taskbar Thumbnails Tuner - According to one person who commented on this page (jonesy), it works in Windows 8.1, but I haven't tested.

At the bottom, check the 'Disable thumbnails' box

Option 4: (I've tested this one)

1. Open Control Panel > System (in icons view)
2. Click Advanced System Settings on the left
3. Alternatively, you can just search for (win+w) visual effects
4. Go to the Advanced tab
5. Click Settings in the Performance area (the top area)
6. Check the Custom box
7. Uncheck the 3rd checkbox - "Animations in the taskbar"

Do what it shows in the first example, but instead of unchecking "Animations in the Taskbar"; uncheck "Enable Peek" instead.