Board Thread:Support Requests - Designing Your Wiki/@comment-44659556-20191218074014/@comment-9605025-20191218154020

There is a file size limit on the background image. My guess is that your file is too large. If order to use an image with a large image size but a smaller file size, you need to compress it. If you do not have the tools to do this (or do not know how), you can use simply online tools such as this.