Do you know you can preview Windows 7 themes before you download them from Personalization gallery through Bing’s Visual Search,though Visual Search is available and accessible from full versions of Bing, you can switch to United States-English .

preview of Windows 7 themes from personlization gallery

Just select a theme and click it, details of theme will be shown like how many wallpapers included in theme pack,preview of those wallpapers shown as thumbnails under Zoom In frame, a brief description about the theme.Click on a particular picture to view the slideshow of all images of theme.

preview Windows 7 themes through Bing Visual Search

If you are not happy with a particular theme, you can select another one and preview it and download the theme to your Computer.

slideshow of wallpapers in theme