You will need to add a section in the Cornerstone and set the padding of it to 0:
Then set the Row settings to be marginless and without container:
After that you can use the Background settings of the Section to add an image which will be full width:
Please consider that this will be a background and it will act as the background and it might cut some part of the image on some viewports. If you want to have an image like the view you need to add an Image element to the section mentioned.