Hi,
you can use User List module.

Customize layout:
Joomla allow you to override module layout, so, you can simply copy attached file into folder /templates/your-template-folder/html/mod_jsnusers/ (create first folder and unzip attached file). This file is an alternative layout to show only avatars, it is based to default layout at /modules/mod_jsnusers/tmpl/default.php
After this you can set this alternative layout from module config (see screenshot)

Filter online users
To filter users you can use module parameter called "SQL Custom Where", to get online users you can fill this parameter with this code:

user_id IN (SELECT DISTINCT userid FROM #__session WHERE client_id=0)

You can see this and other example at our docs page http://docs.easy-profile.com/article/sql-custom-where

Thanks!
how can I increase the size of the image of the avatar?

Hi,
you can manage this with simple CSS code

Ok
I edit my css:

ORIGINAL:
.jsn-l-avatar img {
width: 50px;
}

NEW:
.jsn-l-avatar img {
width: 200px;
}

but so the image is grainy!
How can I do?

Hi,

but so the image is grainy!

the module render thumb of avatar, you can set thumb size from avatar field options

And now I have only photo, I can't display name, surname, username

Sorry I not understand, can you explain me with a screenshot?

Ok
I edit my css:

this is ok, but with your code you change avatar size in all lists, the best way is to add a class to your module and add class in your CSS, so leave original code and use something like
.mymodule_class .jsn-l-avatar img {
width: 200px;
}
to add a specific class to the module you can use parameter "Module Class suffix" in module Advanced options

Hi,
I think that Easy Profile saves avatar image in a file png with dimensions: 100x100px, so when I edit my css to increase the dimensions the png image is grainy!
Instead, if Easy Profile saves the profile images with higher dimension, there is no problem.
Correct?

Yes,
you can set size of stored image from Avatar options (see screenshot).

Instead, if Easy Profile saves the profile images with higher dimension, there is no problem.

Yes or alternative is to use Avatar normal image and not a thumbs, to do this you can simple change onlyavatar.php file, at line 48 replace "avatar_mini" with "avatar"

Hi,
sorry there is a mistake, you ask a module to show only avatar of online users. But from this image seems that you want a module to display current user information, if it is so there is another way, you can use our content plugin and a simple HTML Custom module.

Oh yes there is my mistake..
Ok, how can I use content plugin?