User Photo WordPress Plugin allows a user to associate a profile photo with their account through their “Your Profile” page. Admins may add a user profile photo by accessing the “Edit User” page. Uploaded images are resized to fit the dimensions specified on the options page; a thumbnail image correspondingly is also generated.

User photos may be displayed within a post or a comment to help identify the author. Localizations included for Spanish, German, Dutch, Polish, Russian, French, Hungarian, Brazilian Portuguese, Italian, and Catalan.

Pricing: Free
Requirements: WordPress 2.7+
Source: http://wordpress.org/extend/plugins/user-photo/