Hello @TomasJarvling,
Thanks for writing in!
If you insert a background image into a section and enable parallax, the parallax effect will only be applied in desktop screens. On mobile, it may not look and work as you expected. First, I would like you to try this demo here: https://davidwalsh.name/demo/background-size.html which would explain how background image works.
We use the background-image: cover; which would cover the whole area of the container. This is responsive enough which will always covers the whole area. The only thing to consider here is that if your image size is smaller, it will be stretch out and if you have a bigger image, it will get cut off.
Yes we can use background-size: 100% 100%; which is also responsive but your image will either be stretch out or get squeezed depending on the size of the container.
Yes we can also use background-size: 100% auto; but then as soon as you resize your browser or on smaller screen sizes, you will probably have white spaces around the image.
Or we can also use background-size: contain; but then this is not a good choice because you will see white spaces around your image.
And then, you maybe interested in this article:
“If you look at this page on a cell phone the first picture only has the headline. I would like to place the text that is below above the picture (in the same way as I have done for desktop and ipad).”
Be advised that once you set the image as a background image of the section, it will stay as a background image. Any content you add inside the column will still display the background image of the section. You cannot collapsed and reposition the the image or the headline in mobile.
Hope this makes sense.