Dhaval Kasavala

This plugin allow you display your site all user and their avatar which is selectable what you attach with post.

Contributors role with post

This is simple plugin for contributers with post.

Amarjeet Amar

With gap-hub-user-role WordPress plugin you can change user-role (except Administrator) capabilities easy, with a few clicks.
Just turn on check boxes of capabilities you wish to add to the selected role and click “Update” button to save your changes. 
 That’s done. 
Add new roles and customize its capabilities according to your needs, from scratch of as a copy of other existing role. 
Unnecessary self-made role can be deleted if there are no users whom such role is assigned.
Role assigned every new created user by default may be changed too. 
Capabilities could be assigned on per user basis. 
 You can add new capabilities and remove unnecessary capabilities which could be left from uninstalled plugins. 
Multi-site support is provided.
To read more about ‘gap-hub-user-role plugin’ visit at <a>http://wordpressplugins.gaphub.com/portfolio/gap-hub-wordpress-user-role</a>.
<h3>Shortcuts</h3>
1.For User Login use the shortcut [user-login] on your page. 
2.For User Registeration use the shortcut [user-registeration] on your page. 
3.For User Profile use the shortcut [user-profile] on your page.

gap-hub-user-role.

gap-hub-user-role WordPress plugin makes the role capabilities changing easy. You can change any standard WordPress user role (except administrator).

Contributors role with post vs gap-hub-user-role.