It is important to set expectations with your clients in as many ways as you can - it is a principle that is deeply ingrained in Sprout Studio in a variety of ways.
When your client first views their gallery, you can optionally include a Welcome Message to greet them. For example, you may want to remind them what they have included in their collection, give them instructions on downloading their images, tell them about the expiry date of the gallery, and so on.
There is no welcome message in a gallery by default, so nothing will be displayed. To add a welcome message to a gallery:
Click the "Settings" button on the right-hand side of the gallery.
Click on the "Experience" section in the gallery settings.
Click the "+ Attach" button in the Message Template section in your Gallery Settings. To create new message templates, go to Settings > Galleries & Designs > Gallery Messages to create, edit and manage your message templates.