cannot centre-align images anymore

Hello,

I’m using Savona Edge. At the beginning everything was alright. Then, something changed and now when I post an image in my blog, it doesn’t centre align anymore (the problem occurs already in the editor, not only in the visual)
I think maybe I touched something in Simple Image Size, I shouldn’t touch.. but I’m not sure..
The only new plugin installed recently is Nice Likes. I don’t know if this plugin could affect it?

I tried to add new CSS like:

.aligncenter {
	clear: both;
	display: block;
	margin: 0 auto 1.75em;
}

or

div.aligncenter {
display: block;
margin-left: auto;
margin-right: auto;
}

but they don’t make any difference.

Someone could help?

Thank you very much

The page I need help with: [log in to see the link]