Board Thread:Support Requests - Designing Your Wiki/@comment-46819896-20201019203804

So, my wiki (Police Story Wiki) needs a background. (Im currently using the default diamond plating background.) I want to use File:Police story bg.jpg. Ironically enough, whenever I use the template (may be out of date) the image fits the templates dimensions. Can anyone help and tell me what I'm doing wrong? I do everything correctly, even going as far as to upload as a PNG, but it still won't work. Please help. 