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JEMH won't create many copies of the same image, all attachments are checked for uniqueness and only added if different.  Even then, removing specific files such as email signature images can be done using Blacklisting (JEMH>Blacklisting), see Use Blacklisting/wiki/spaces/JEMH/pages/2850907.

Results

With the image blacklisted, it won't appear again, either during creation or comment.

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