But as of yesterday, Internet Explorer 7 users can no longer customize the background of Google. Instead, if they want a custom background, they should upgrade to IE8 or IE9 or switch to Chrome, Firefox or Safari.
Albert from the Google team said in a Google Web Search Help thread:
Apologies for the late reply! We are no longer able to provide support for background images for Internet Explorer 7 users. Please try upgrading to IE8 or using an alternative browser, such as Google Chrome or Mozilla Firefox, to be able to see background images again.
I personally do not use the feature but I am sure plenty of IE7 users do.
Forum discussion at Google Web Search Help.