There are a number of ways for users to have photos in Lync 2010 but my preference is to store them in Active Directory because they can then be reused by Sharepoint, Exchange / Outlook and other applications.
This is a quick post about the easiest and cheapest way I have found to do this. I’m assuming that you already have your user photos.
Firstly, obtain and install Picture Resizer from here. I used the following options “-o -f96x96 -q100″. This meant that I can easily right-click on a user photo and have it resized to 96 x 96 while maintaining photo quality. This still results in image size reduction, which we are aiming to have well under 30KB to avoid bloating the AD database.
Next, install a piece of software by a guy named OliD that extends the Active Directory Users and Computers MMC with two tabs on the user properties page – from here. Read the installation instructions can be found in the .zip file.
Once installed you will have a Photo tab in ADUC. Select your newly resized photos and add them to to the thumbnail section.
More useful info here and here.