@freeplay This issue has been resolved in my Mastodon fork (Fedibird).
According to Misskey, it allows up to 16 (or less than what is specified in the server settings), after which it will display that number and a link to the original post.
The WebUI look could be a little better.
Most client applications support 5 or more images and display them well.
I'd like to open a pull request to the mainline someday.
@freeplay If you set 4 acceptances, you will get a link like this when you exceed it.
This link will take you directly to the public post on the remote server. (So it won't work because it can't be seen on followers-only posts)
I think that the limitation in Mastodon is because we want to reduce the number of cases we accept, so we need to consider some kind of workaround at the same time. This is one of them.