Image caption do not work

i add the code form this post
https://www.ads-software.com/support/topic/223511?replies=2

now the border are there but the images is not centred inside the grey border

I’ve add this code from codex document

so how do i make the images centered inside the caption?

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

.alignleft {
   float: left;
}

.alignright {
   float: right;
}

.wp-caption {
   border: 1px solid #ddd;
   text-align: center;
   background-color: #f3f3f3;
   padding-top: 4px;
   margin: 10px;
   /* optional rounded corners for browsers that support it */
   -moz-border-radius: 3px;
   -khtml-border-radius: 3px;
   -webkit-border-radius: 3px;
   border-radius: 3px;
}

.wp-caption img {
   margin: 0;
   padding: 0;
   border: 0 none;
}

.wp-caption p.wp-caption-text {
   font-size: 11px;
   line-height: 17px;
   padding: 0 4px 5px;
   margin: 0;
}