Chnage the Thumbnail Size in Windows XP:

1. Open Registry Editor.

2. Navigate to the following Registry Value.
For Current User: HKEY_CURRENT_USER
For All Users : HKEY_LOCAL_MACHINE--> Software – Microsoft – Windows – CurrentVersion – Explorer

3. Add/Modify the following entry.ThumbnailSize - Double Word - Value: 32 - 256ThumbnailQuality - Double Word - Value: 50 -100

4. Reboot the PC to take effect.

Note:

Editing the Registry will cause the System unstable. Please take a Proper Back-Up before editing with Registries. Author will not be responsible for any liabilities.