Uncomplex has tweaked Mailplane, its WebKit wrapper for Gmail, with a handful of minor fixes and improvements. Picture optimization in outgoing messages can now be controlled via AppleScript, dragged messages now disappear as expected, dragging images onto Mailplane's icon now optimizes pictures reliably, and keyboard shortcut functionality broken by Gmail changes has been restored ($24.95 new, free update, 19.9 MB)
Fun Way to Send Attachments in Mail
If you're working in a file that you want to attach to a message in Apple Mail, you can transfer the file to Mail easily: From the title bar of the file's window, drag the little proxy icon to Mail's icon on the Dock. Your Mac will make Mail the active application and open a new outgoing message, with the file attached.
(If your icon won't drag, the file probably isn't saved.)