In your code above, that would add the image “inline” which means it wouldn’t be a “background” image (but it will show up). If you want an actual background image, then you would need to add that in your css to the “slider-wide” on line 1146 – background: url(http://hardmoney.com/wp-content/uploads/2014/05/New-York-Properties2.jpg);. If you’re only planning to add just one image then you don’t need to use a slider, just add the background image from the code above.
Also, in your code above, it probably didn’t show up in your widget because it was missing a " at the end.
Here’s what the end result should look like if you want to add it in your css –
.slider-wide {
background: url(http://hardmoney.com/wp-content/uploads/2014/05/New-York-Properties2.jpg);
clear: both;
width: 100%;
}