When I display a collection of user pictures (for example, those users who have tagged some content), hovering over each just displays "View user profile". As I'm not displaying the user's name anywhere else in this list it would be useful for the title attribute on the image to include the user's name.

SOLUTION:

Change function imagecache_profiles_preprocess_user_picture line that reads:
$title=t('View user profile');
to match what is done with the alt attribute further up:
$title = t("View @user's profile", array('@user' => $account->name ? $account->name : variable_get('anonymous', t('Anonymous'))));