I will teach people how to add background to your pages. I got the tutorial from Ben CleverName, and since not many people did read his comment on one of the request post, I will post this.
I prefer the moderators themselves adding the background, because if not so, the purpose of original pages with existing background will amount to nothing. After all, to please my superiority complex. Anyway.
Step 1 - To add the image you want it to be the background, you can choose one of these 2 ways.
Move your mouse to the 3 dots and click on "Upload New File".
It will move you to this page, click on the "Choose Files" to upload your image.
Or, you move your mouse to Explore, and click on Images.
It will move you to this page, click on the "Add New Image" to upload your image.
Step 2 - Move your mouse to empty area, click on them and write the {{ to open the template setting.
Type "background" and click on result.
Then click on "file" and type on the space created the name of the image you imported.
After doing that, save your page and refresh them, if need.
This is my page before the edit.
And this is it after the edit.
If you want to edit by Source Editor, type this.
{{Background|file=name of file you want to import}}