I have tried adding a background image to a couple different themes and have run into the same problem and I have no idea why, but it is driving me crazy. When I add the image (1320×1020, but I have also tried 960×741 and 760×587) it gets tiled and then when I click “no repeat” I only get one small picture that is displayed. How can I make the picture take up the whole background without tiling? I have tried the Oxygen theme and the Twenty Twelve Themes. Do only certain themes use one large image and all the rest automatically tile? Is my image the wrong size? Are there further customizations that need to be done to make this work?