I believe there are some 3rd party options that will download everything if that's what you want to do. A quick google search found a couple options.
Yes, but that is a manual thing. One file or photo at a time. You can only get a complete archive for your own yahoo account. Not for a group.
Ben
On 17 Oct 2019, at 18:46, jpb@gmx.at [PolySix] <PolySix@yahoogroups.com> wrote:
I think you should be able to download all files from the group, perhaps they could be accessible on some free cloud service: