You mean the black portion in the footer? Just change the padding on #copyright.
Problem is that I want to remove any text from the footer, increase the height and add the image. But there is another theme about the image adding.
So how to increase the height of the footer if there is no text?
Then you should just set the height of footer. Something like this:
#copyright {
clear: both;
padding: 1.4% 3.2%;
background: rgb(17, 17, 17);
border-top: rgb(51, 51, 51) 1px solid;
color: rgb(204, 204, 204);
font-weight: 300;
height: 50px;
}