Is there specific requirements for uploading a custom background image into VisualRF in AirWave? I've tried uploading a file that was 2000x1200px, 1200x600px, and most recently 400x150px and the background image will not update. I've tried refreshing the campus, but still blank. If I set the world map ones it loads instantly. Is there a specific dimension or file size requirement I'm missing?