All the solutions that joomlaplates has given me are very useful, but my client wants to be private during the design process, for that reason I am deleting the URLs, are there possibilities of having the conversation in private?

No problem, I have deleted the screenshot with URL.
BTW did you solved the problem?

No, I have followed all the instructions that you have given me and I can't solve, the problems of the bg only happens when the ipad is folded in landscape.

Hi there,
in landscape the tablet have a width of 1024px width, therefore you have to change the media querie to 1024px:

@media screen and (max-width: 1024px) {
#top-a, #top-b, #top-c, #top-d, #bottom-a, #bottom-b, #bottom-c, #bottom-d {background-attachment:scroll !important}
}

With this change in custom.css everything is solved, I appreciate your great effort.
I would like your instructions to stay in the forum, because they will serve others for the same problem.
How can I erase a graphic that I previously sent as an attach, since it allows me to modify the text, but not to unpublish the image?

I have deleted the image.
But you could do it by yourself with remove the "tick" at the attachement