Currently when we get a mail from an external client (e.g.- Outlook) and if it contains an animated GIF image in the signature of the user and if the same user has replied/forwarded in that mail multiple times, then some email clients will store the actual image only once and just give references of the image at all other places. So the total size of the mail will be lower.
If we reply to this mail from Notes Client, then Notes Client will store the image each time so the total size of the mail can increase considerably. If that image is of size say 1.5 MB and if the user has replied 25 times then the total increase in the size will be around 35 MB when we reply from Notes Client.
So there is a feature request to modify the Notes Client MIME source generation function to store the same image only once and just give its references at all other places. This is important because large size mails like 40 MB or more are often rejected by external domains due to size restrictions.