I have come across a number of customers who want to have staff photos visible in their GAL. They typically look at this feature when migrating from previous versions of Exchange to 2010. Though Microsoft supports this feature with the use of PowerShell, Exclaimer Outlook Photos gives a free GUI tool – not just for you to try, not just for a limited period, not with feature limitations but absolutely free.
The tool can be installed in any domain joined machines – any one from XP to 2008. Check the system requirements here
Download the tool here