The orginal question was regarding how to add a custom image divider or border at the bottom of WordPress posts.
Example #1
.postmetadata {
clear: left;
line-height:20px;
color:#ffdc8e;
background-repeat:no-repeat;
padding:10px 0px 10px 0px;
margin:0px 0px 0px 0px;
text-align:right;
border-bottom:solid 1px #0f4254;
}
Example #2 – adding your own custom image as the divider / bottom border in posts
.postmetadata {
clear: left;
line-height:20px;
color:#ffdc8e;
background-image:url(images/your-custom-divider.jpg);
background-repeat:no-repeat;
position: absolute; left: 0; bottom: 0;
padding:10px 0px 10px 0px;
margin:0px 0px 0px 0px;
text-align:right;
}
If this is WordPress Theme you are coding from scratch you will obviously need to create a style.css. Good Luck!
Official WordPress Resource Page on CSS