Custom header on the journalist theme

Hi I’ve just changed themes and I’m running a older version of the ‘the journalist’ at my site at https://www.theblackwaterfall.com and I’m looking to put in place a customised header, I found this code

#container h1 a {
display:block;
text-align:left;
background:url(‘https://….’) top center no-repeat;
height:340px;
width:950px;
text-indent:-9000px;
}

I’ve tried putting my image in here and I get a blank space that fits these dimensions where the header should be (see site link). Can anyone tell me why this is please. thanks, christian
ps. happy new year:)