Touch Stay has separate tabs for photos & videos depending on where the media was originally uploaded, Content Hub has a media tab and every Guide will also have its own media tab. There’s no difference between them other than providing separation of the media to help organise your photos and videos easier. When selecting photos or videos for topics (and cover photos) you can always access photos or videos from other Guides, or Content Hub, by using the “Filter media” option at the top of the photo selection section.
The first block of media will be photos which match your chosen filter, keep scrolling down for the videos section. The photos and videos in the selection screen will display in the order in which they were uploaded. This is only relevant to the media tabs and media selection screens, the photos/videos will show in your guest view only when attached to topics of content and will therefore follow the topic order. To reorder your topics see this article.