Know GMail more

• Although GMail copies whole history when reply, it rather assumes that we retain only necessary part relevant to latest corresponding.  That's why the copy is called "quoted text" and placed before ending signature.
• Given standard image sizes in GMail (small, medium, large, original) may not fit. But we can drag image boundary-handle to resize manually.
• Signature, as defined in Settings, will be coloured in gray when sent. 
• There may be a myth amonb beginners that  new recipient can see older mails in conversation thread, it is not true.
• Deleted mails are retained in trash for 30 days.  Therefore:-
  • Treat [Delete] as rather "pending deletion".  If we think a mail can be deleted if there's no issue after a while (i.e., 30 days), then we can delete it from day 1.
  • If we think a mail must be deleted now (e.g., for some private/confidential reason), we have to "double delete": go to Trash and [Delete forever] it again too.
• Apart from "Forward" function when you respond at the end of mail/thread, there's also another "Forward all (messsages of this thread)" function listed on the right.
• A useful function is "Recent conversations" (context menu when point to contact name: sender or chat) when we are going to call/talk to that person that it may recall a few more to discuss altogether with our tentative topic(s) in mind.