The very simplest thing is to set up a static "downloads" folder on the server in Apache or NGINX and just let the user browse it. This used to be the default behavior, and if there's no index.html, the user just sees a "folder view". Since the browser renders it, the exact appearance depends on the browser, but it typically just looks like your desktop file browser.
I think some modern web server guides recommend blocking this kind of access, but I think it's fine, so long as it is restricted to a particular folder and you don't put anything in there you don't want people to see.
There are also static "gallery" generators, although they have gone somewhat out of fashion and tend to look kind of dated, now. These will show the image content better, though.