I work alot with ArcGIS Online and StoryMap and use many different public wms layers for each new location I find. Due to the amount of layers I use adding the map 10-15 times in a story with different layers makes it very slow and crashes (I get the "out of memory" error code). The workaround this problem is currently just screenshotting the map and adding it to the story as a picture, which leads me to posting this.
I really wish there was an option for adding an image in the main image in the sidecar. A smaller slot in the left corner so that it is possible to upload a legend manually. As things are now I have to add the photo of the legend in the text, which makes it a bit messy.