There is now a third method that compliments the other two.
Outlook 2010 has a feature called the Outlook Social Connector (OSC) that can show photos in Outlook from Linked IN, Facebook, etc..
The Solution: Epicenter Server gives your users their own local copy of the corporate address book.
Then Active Sync synchronizes those changes to each user's device. The address book could be your Exchange GAL, an Exchange address list, or an Exchange Public Folder.
The Global Address List (GAL) has not updated from Active Directory.
The Microsoft Exchange default is for this to update at 5 AM each morning.
Additions, deletions and changes are automatically applied to keep contacts up to date.
No additional software is required on the phones or tablets.