In particularly long message strings the images embedded in signatures below the last response (i.e. added to previous messages in the string) may not be displayed correctly. They can be either completely removed or changed, e.g. with their quality significantly reduced (Fig. 1.). 

 
Fig. 1. Image completely removed from the signature below the last reply.

The reasons of such behavior are the very mail clients that were used while replying or forwarding emails in the message string. Every time a user clicks the Reply or Forward button, the whole message source is modified by the mail client software – reply header is added, place for the response text is prepared etc. During that procedure the images in the message may be compressed, modified or even removed – according to the respective client program and its settings.

After the procedure described above is complete and the message is sent, it travels to the Exchange Server where the signature is added to the latest response text by the CodeTwo Exchange Rules software – and images in this signature will be correctly displayed.

There is no direct solution to this issue, since there are too many email client programs available (including all mobile phones and PDA devices), and they all may have their own procedures of processing long message strings and images embedded in them.