Originally Posted by
WillCAD
And it only downloads in the same way that a web page downloads when you're viewing it in a browser - a temp copy on the device which is non-persistent.
This is actually up to the IMAP client. Most clients can be configured to maintain a local cache, which is accesible when the device is offline. K9 for Android certainly can, and does by default.
Originally Posted by
WillCAD
I don't think the phone retains any 'trash' copy, though I believe that the server has a trash folder for recovering deleted mails.
Most IMAP clients do cache the trash folder, which is just a normal folder as far as the IMAP protocol is concerned.