Is it possible to use rules to set user profile pictures?
Create a componnent in rule with this ! On the componnent you have 2 parameters. One for the user and another one for the file you want to use ! I use Drupal 7.

$uid = $user-&gt;uid;
$account = user_load($uid);
$thefile = file_load($file-&gt;fid);

$edit['picture'] = $thefile;
user_save($account, $edit);


Call the componnent from the rules you want. On my side i'm using a flag to trig the rules. The user mark an image to use it has a profile picture and it work. 

I use this link has a starter to create the rule. http://taggartjensen.com/code-snip/drupal-7-set-user-picture-programmatically

Good luck !