A browser's Copy Image puts the picture on the clipboard with the image's
address as text (and HTML). Paste takes text before bitmaps, as word
processors offer a picture of copied text, so it pasted the address.
- `clipboard::is_address`: text that is only an address (http, https,
file, ftp, data or blob).
- Desktop paste (Windows, macOS, Linux): such text gives way to the
clipboard's bitmap when it has one. An address alone pastes as text, as
before; nothing is fetched.
- Web: a paste whose text is only an address takes its picture file.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>