We have just launched a story map for the Waterford Greenway see
We did want to have an image display on the first tab (Welcome) but found that if you use an image on the first tab and have the Synchronize map locations set the map centres on the screen and allows the legend to overlap, even if you have it set not to allow this.
While you can fudge this for the desktop by offsetting the location in the web map, the map then appears off centre when viewed on mobile devices.
Note: As soon as you replace the image with a map on the first tab everything works OK.
I hope that makes sense. Let me know if it doesn’t and ill attempt to clarify.
FYI Michael Kelly