Documents icon did not showing up in search result - Sharepoint 2010

Picture is from Google :)

Some of my users complaint that they did not see the document icons in search result - after we installed the iFilter.

When we check, the source of the images is empty. (src=" ")

But it is weird because certain users can see the document icon perfectly.

After investigation, we found that there are double mapping key in xml file (docicon.xml).

<Mapping Key="pdf" Value="pdf16.png"/>

<Mapping Key="pdf" Value="pdf.gif" OpenControl=""/>

After removed one of the mapping key the search icons were displayed perfectly for all users. 

I am now happy :)