@evan-shulman This setting is use in case you have multiple domains attached to a project, when checked, all other domains (including the temp url .appdrag.site) will redirect to your main domain.
Hello, it is not possible. You could use the blog module with a category per gallery to use its pagination system but that would index the blog detail page for each of your gallery image (which can be a good thing if you specify title and description but a bad thing if you don't).
You can also create a Cloud Database and do some JavaScript code but it's a bit more difficult. (We can find a partner who can do it for you, it would take one hour, two maximum)