Hi Tom,
Presently, we do not support fixed background images. All row background images use the responsive CSS property of `background-size: cover` and the default scroll state for the `background-attachment` property. We do have an issue slated to add a control that would allow you to set `background-position` which allows you to center the focal point around which your image will responsively resize and we may be able work `background-attachment` in during that time. But unfortunately, there isn't a very clean way to do the CSS to override it as-of-today since none of the rows have unique classes on them and you should not use the dynamic ember IDs as those change.