INSANELY stubborn post-image align issue (Centered images only)

I think I’m victim of the most insanely stubborn post-image alignment issue I’ve seen around the forums;

I’ve tried EVERY revision of code I could find to fix this ridiculous problem, and as of yet, nothing has worked. Maybe someone can shed some light. Here is an example of my qualm:

The Bowie Quote is meant to be centered in the post box, which it [obviously] is not. Not only that, but WordPress is completely ignoring my <p> tags as well. And for some reason, finds it additionally humorous to delete my tags, which I tried using to remedy this multifarious complication.

Please help me or my head might explode. Cheers!

(Btw, here is what my stylesheet [style.css] currently looks like):

/*img.alignright { float:right; margin: 0 0 1px 5px; padding: 2px;}

img.alignleft { float:left; margin: 0 5px 5px 0; padding: 2px;}

img.aligncenter { float:center; margin: 0 5px 5px 0; padding: 2px;}*/

img.alignleft, div.alignleft {
float:left;
margin:2px 2px 2px 0px;
}
img.alignright, div.alignright {
float:right;
margin:2px 0px 2px 2px;
}
img.aligncenter, div.aligncenter {
float:center;
text-align:center;
margin:2px 2px 2px 2px;
}

/*img.centered, .aligncenter, div.aligncenter {
	display: block;
	margin-left: auto;
	margin-right: auto;
	}

img.alignright {
	padding: 4px;
	margin: 0 0 2px 7px;
	display: inline;
	}

img.alignleft {
	padding: 4px;
	margin: 0 7px 2px 0;
	display: inline;
	}

.alignright {
	float: right;
	}

.alignleft {
	float: left;
	}*/