In this post we will discuss how to change DocIcons in SharePoint 2010 sites.
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Follow below steps to change the DocIcons:
Save your DocIcon image (.gif image) in the below location C:\Program Files\Common Files\Microsoft Shared\web server extensions\14\TEMPLATE\IMAGES.
Then Open DOCICON.xml file from the below location:
C:\Program Files\Common Files\Microsoft Shared\web server extensions\14\TEMPLATE\XML
This is the file where all the DocIcons has been registered for SharePoint sites.
Then add this "<Mapping Key="pdf" Value="pdf.gif"/>" and the save the file.
Remember: Changes to DOCICON.XML should be made with extreme caution because they are global to a Windows SharePoint Services deployment and affect all site definitions on the front-end Web server. And also Changes that you make to this file may be overwritten when you install updates or service packs for Windows SharePoint Services, or when you upgrade an installation to the next product version.