Alignment doesn't work

http://extensions.joomla.org/extensions/edition/editors/12821

I will try check Joomla extension with your tamplate ASAP. Please be patient.
This can be of course problem with template and extension compatibility. I will give you a note when I check this.

Please paste here link from which you get your template. It will be a little fast to check this .
EDIT:
Have you change anything in your template ?

In what way you try 'center' image ? You use align option in image dialog or 'center' button in CKEditor buttons ? I tried 'center' button and it works fine with your template.
What settings do you have in "Use template CSS" option in "Advanced Settings" tab in CKEditor component configuration ?

Hi @beBoss,
I checked this and it works ok from editor's side, but you have right after save (on page) image isn't in center. The problem is with template.css.
Please look at attached screenshot : the blue frame shows table inside which is 'p' tag. In this 'p' CKEditor put its content (which is center as you see). Because of

 table class="contentpaneopen"

width image looks like not in center.
In file pathToYourJoomla/templates/siteground-j15-14/css/template.css line 477 please change:

table.contentpane {
    margin: 0;
    padding: 0;
    width: auto;
}

to

table.contentpane {
    margin: 0;
    padding: 0;
    width: 100%;
}

than you will see that image is in center.