Board Thread:Support Requests - Designing Your Wiki/@comment-33688175-20200317170752/@comment-9605025-20200520223117

Assuming the background of your images are transparent (as is for Wikipedia and Segment Displays Wiki), the background color is set simply by the background color of the element containing the images. Otherwise, you would need to make the background of the image a color you want. As for the colon, that would also need to be an image.