The recommended image sizes are as follows:
NOTE: The theme will automatically zoom in whatever image you use here, so it’s recommended that you leave a little room around the edges of your big title image. If you have text or an image that you need displayed fully, then keep it around the middle section and leave a little background space around the edges.
Please note that the theme comes with a dynamic image resizer that will automatically stretch or shrink any image you upload. However, you should make sure that you use images that are close to the sizes listed above, because if the image is too small or too large for the area, the resized version will appear fuzzy or pixelated.
Also keep in mind that the ideal number of pixels is 72dpi but you shouldn’t worry about that too much, as most stock photos have a great picture quality that you can use without having to modify.