Change Background Image on mobile : image custom file keep disappearing

Site URL: https://helicon-mackerel-9k6a.squarespace.com/

Hello,

I have followed rebecca's tuto to edit all the background image on mobile.

When I do that it seems to work well but the issue I have is that mobile images keep disappearing. The link generated with the custom files for the images to not redirect to an image. It looks like Squarespace remove that image from the custom files.

What should I do to solve that problem?

Here is the code structure I have used for each section where I wanted to show a new image

@media @mobile {
/* Insert Code for Mobile Below This Line*/
  [data-section-id="5f2ab4412795162792d107f8"] {
    img{
      display: none;}

.sqs-block-image img {
display: block;
}
.section-background {
background: url("https://images.squarespace-cdn.com/content/5f2408dcdc63bd117de38332/1601648650311-24MSK5GFD0N999FOUBNF/Artboard+Copy+13.JPG?&content-type=image%2Fjpeg");
background-repeat: no-repeat;
background-size: 100%;
}
}

If you do try to open the link mentioned in the code, you will see that it doesn't work, but I am sure it has worked when I created it.

https://images.squarespace-cdn.com/content/5f2408dcdc63bd117de38332/1601648650311-24MSK5GFD0N999FOUBNF/Artboard+Copy+13.JPG?&content-type=image%2Fjpeg

If someone can help me on that, that would be really great 

Just had a discussion with an agent from squarespace

It looks like images that are removed from the website will be deleted from Squarespace. 

So Rebecca's Tuto doesn't work anymore. Does someone have a solution for that?

Create a new hidden page. Place the image on that page.