Hi Nik-
I checked out the site you sent over privately, and it looks like you’ve solved this pretty creatively by deleting the image file.
Kudos for the solution! But, I would like to warn you that when the theme gets updated the image background will reappear.
It looks like you actually had the code very close to correct, the only problem is the period (.) right before body. You had:
.body.custom-background{
background-image: none !important;
background-attachment: scroll !important;
background-color:#ffffff !important;
}
Instead, try this:
body.custom-background{
background-image: none !important;
}