When you add new items to SharePoint 2010, a new icon appears beside the title of added item as the below image.

The default time period of this new icon is 2 days. You can modify the time period by using the stsadm command.

In this example, the new icon will disappear after 5 days:

stsadm -o setproperty -propertyname days-to-show-new-icon –propertyvalue  5 -url http://website

The time period can also be changed with PowerShell.  In this example, the new icon will also disappear after 5 days:

# Set to 5 Days $webApp = Get-SPWebApplication "http://WebAppURL/" $webApp.DaysToShowNewIndicator = 5 $webApp.Update()
To stop the new icon being displayed:
# Set the days to display to 0            
$webApp = Get-SPWebApplication "http://WebAppURL/"             
$webApp.DaysToShowNewIndicator = 0             
$webApp.Update()
If you have a
custom ItemStyle and you want to show the new icon beside the title, just add the following:

<xsl:value-of select="@Title">
</xsl:value-of>
     <xsl:if test="ddwrt:IfNew(string(@Created))">
          <img src="/images/new.png" alt="New" border="0"/>
</xsl:if>