Some windows users like to use the thumbnail view, especially for browsing through photos and images. It can become a bit of a drain on your system. It is possible to lower the thumbnail size and quality by editing the following registry keys.
First, u need to goto Start, then run.
1. Type in regedit in the box.
2. Then, navigate to :
HKEY_CURRENT_USER\ Software\ Microsoft \ Windows\ CurrentVersion\ Explorer
Create a new DWORD value called ThumbnailSize, and set the value between 32 and 256.