It's not in Aero.mssyles nor explorer.exe and most used DLLs.

Hello my friend, I hope you are well

Warning

You must have the Windows Aero color scheme turned on for the Glass Transparency, Taskbar Thumbnail Previews, and Flip 3D features.

HARDWARE REQUIREMENTS FOR: WINDOWS AERO
See: Windows Help and Support: Troubleshoot problems with Windows Aero

NOTE: The Windows Aero color scheme is not available for the Vista Home Basic edition.

1 GHz 32 bit or 64 bit CPU processor.

The computer needs at least 1 GB of RAM.

A graphics card with support for DirectX 9 graphics with 128 MB of memory.

The graphics card must support Pixel Shader 2.0 in hardware.

The graphics card driver must support Windows Vista Display Driver Model (WDDM)

The computer display color depth must be set to 32 bits per pixel.

EXAMPLE: Enabled and Disable "Show preview windows
(thumbnails)" Option

NOTE: You can see this by right clicking on the Taskbar and clicking Properties.

>>head <<

Through the Local Group Policy Editor

NOTE: This method is only available for the Vista Business, Ultimate, and Enterprise editions. See Method Two or Three below for the Vista Home Premium edition.

1. Open the all users, specific users or groups, or all users except administrators Local Group Policy Editor for how you want this policy applied.

2. In the left pane, click on User Configuration, Administrative Templates, Start Menu and Taskbar. (See screenshot below)

3. In the right pane, right click on Turn off taskbar thumbnails and click on Properties. (See screenshot above)

4. To Enable Taskbar Thumbnails

A) Dot Disabled or Not Configured and click on OK. (See screenshot below step 5A)

B) Go to step 6.

5. To Disable Taskbar Thumbnails

A) Dot Enabled and click on OK.

6. Close the Group Policy Object Editor window.

7. Log off and log on, or restart the computer to apply the changes.

What