[Feature]: Add the ability to copy images

[nuranyak]

Description

It would be great if it were possible to copy images from attachments to the clipboard

Suggested Solution

I have no idea if this is technically possible on iOS, but I have a fully functional proof of concept solution for Android, see mastodon-android#1064 (It adds a copy button next to the download button)

Alternatives

No response

Additional Context

No response