Note there are a couple of cosmetic issues you may notice when defining or changing the cover page for a side-panel Map Tour in the builder.
1.
You can't use a video instead of an image for the cover page for a side panel layout. The Story Map Cascade''s cover page supports video but Story Map Tour's cover page doesn't. The Map Tour Builder will let you select a video, but when you preview or open your tour outside of the builder, you'll notice that it doesn't work. There is a message in the builder saying that video isn't supported but we don't prevent you saving your tour in this case.
2.
If you are using Internet Explorer or Microsoft Edge, when you view the cover page configuration in the Story Map Tour, your image doesn't appear in the Builder: you just see a grey box instead of the image. This looks bad but don't worry because the image will still work, and you'll see it if you preview or open your tour in a new tab. You can replace that image in the Builder with a new one successfully: you just won't see the new image in the builder. We (actually I should really say I) somehow didn't spot that in time to fix it for this first release . We'll look to address this in the next release.
3.
If your cover page image is defined via a URL link to an image (i.e. a Flickr image or an image on any server that you are referencing via a URL) and you click the little pencil icon in the top left-hand corner of the cover page image to change or review that URL, the URL isn't shown in the little dialog that popups up, Don't worry because that image will still work, and you'll see it if you preview or open your tour in a new tab. You can paste in a different URL to replace that image with a new one successfully too: You just won't see that URL in that dialog the next time you open that. This is not an issue if you are uploading your images directly into the Map Tour Builder. In that case clicking the little pencil icon in the top left-hand corner of the image lets you browse to a different image to upload: it doesn't show you a URL. We'll look to address this in the next release.
Rupert