Another member of the team added an attachment to the wrong card in Trello.
Is it possible to move this attachment to the correct card on another list (same board) without downloading, deleting, and re-attaching it?
There is not (currently) a way to move an attachment from one card to another without going through the download, delete, re-attach process you've described.
When displaying the card with the attachments to want to move, open another window of your browser (e.g.
ctrl-n in Firefox).
On the new window, open the card to receive the attachments.
Open in New Tablink.