Resolve problem: Windows 7 cannot display thumbnail image

Few days ago, when I viewed my folder which contain images, it displayed as the image bellow instead of thumbnail image:


It's really inconvenient! I thought that my Windows had an error but after search on the internet, I found the simple way to resolve it:

In the Explorer window, go to Ogranize -> Folder and Search options -> View -> Untick the checkbox Always show icons, never thumbnails -> OK

Now, my image folder was displayed as expected