Change Taskbar Thumbnail Size with Regedit

Adjusting the taskbar thumbnail preview size in Windows allows you to customize the dimensions of the pop-up windows that appear when hovering over active taskbar icons. By modifying specific values in the Windows Registry (Regedit), you can increase or decrease the pixel size of these previews beyond the default settings. This guide walks you through navigating the Registry Editor, creating the necessary registry value, setting your preferred thumbnail dimensions, and restarting Windows Explorer to apply the changes.

Step 1: Open the Registry Editor

  1. Press Windows Key + R to open the Run dialog box.
  2. Type regedit into the field and press Enter or click OK.
  3. If prompted by User Account Control (UAC), click Yes to grant administrative permissions.

Step 2: Navigate to the Taskband Key

In the Registry Editor address bar at the top, paste the following path and press Enter:

HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Taskband

Alternatively, use the left-hand navigation pane to browse to the folder manually.

Step 3: Create the Thumbnail Size Value

  1. Right-click on the Taskband folder in the left pane, or right-click any empty space in the right pane.
  2. Hover over New and select DWORD (32-bit) Value.
  3. Name the new value MinThumbSizePx and press Enter.

(Note: If the MinThumbSizePx value already exists, you can skip creating it and proceed to the next step.)

Step 4: Set the Desired Thumbnail Size

  1. Double-click the MinThumbSizePx entry to open its edit window.
  2. Under the Base section on the right, select the Decimal radio button.
  3. In the Value data field, enter your desired preview size in pixels.
    • The default Windows preview size is roughly 200 pixels.
    • For larger previews, enter a value such as 300, 350, or 400.
    • For smaller previews, enter a value lower than 200 (such as 150).
  4. Click OK to save the changes.

Step 5: Restart Windows Explorer

The registry changes will not take effect until Windows Explorer is restarted.

  1. Press Ctrl + Shift + Esc to open the Task Manager.
  2. Under the Processes tab, locate Windows Explorer.
  3. Right-click Windows Explorer and select Restart.

Once the taskbar reloads, hover your cursor over any running application icon to view your newly resized thumbnail previews.

How to Revert to Default Size

To restore the default thumbnail size at any time:

  1. Return to HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Taskband in Regedit.
  2. Right-click MinThumbSizePx and select Delete.
  3. Confirm the deletion and restart Windows Explorer via Task Manager.