Zoomed in and low quality pictures

Is there a way to stop the header picture from looking blurry when applied?
Also, how do I make it so the background picture fill the entire background instead of multiple smaller pictures?

To make your background just one with out a repeat ty this in your CSS files.

Code:

body {
    background-size: cover;
}

Warning the background is really small so it might look really bad you should always use a bigger background for that part of the forum.

As for the banner sadly there is not a lot we can do as the image is not tat good to begin with.

Thanks.
See, that's the thing, the picture I used for the background is actually 3840x2160 in hoping that it wouldn't do the repeating pictures.

Hm.. didn't work, only made the upper half of the background fill out the whole screen

Did you add the background image in the non-CSS way?  If yes, did you check the box that says do not repeat?

I added the picture like this in the simple version of the pic management.
Then I did this in the CSS sheet under color
Which then gave me this which for some reason makes the upper top of the background fill out the whole upper page, while the bottom part of the background page, is still repeating.

And I tried adding no repeat in the CSS, but didn't change anything

Wait a minute!  Is this the forum in question:  https://super-heroes.forumotion.eu/forum
If yes, your forums are so wide that you really do not see too much of the background image.

yes, that is the forum in question.
in what way do you mean the forum is so wide?

Wut?! Wild, it show a lot of free space for me in the sides

Must be because of my 2540x1440 monitor