Board Thread:Support Requests - Designing Your Wiki/@comment-38546904-20200112205020/@comment-9605025-20200113033431

Yes. If I am understanding you correctly, you want to have the image cover the entire width of the background. Do accomplish this, you need to do one of the following: If you are willing to use custom CSS, you also have the option of stretching the image. However, that will result in a loss of "quality"; which you said you wanted to avoid.
 * 1) Use a larger image
 * 2) Tile the image
 * 3) Allow splitting of the image (i.e. have a colored line run down the middle)