Take a look in your style.css file in the Front Page section of the CSS and remove or adjust the padding starting on line 1539 –
.front-page-2 .image-section {
background: #ffffff;
padding: 60px 0 20px;
}
.front-page-2 .wrap {
padding: 0 5%;
}
Then add this to your CSS to remove the margin-bottom that shows up automatically for each widget –
.front-page-2 .flexible-widgets .widget {
margin-bottom: 0;
}
If you’re not using the background color, I would just remove it by adding background: none to this section – .front-page-2 .image-section
Also the .front-page-2 widget is set at 1000px by default on line 1543, but the wrap inside the widget is 960px. Since you want the image to be the background, you’ll need to change the 1000px width to 960px and adjust for the responsive part of the CSS as well.