May i suggest the option of setting one email signature for first emails and another for reply email.

When you start an email conversation or reply for the first time on an email you would often want your email signature to be rich and containing pictures, links to various social networks, links to various of your companies web sites etc.

But as you engage in a email conversation with a client you do not want that rich email signature with images, links etc. to be included in those emails.

I therefor suggest that you include in option to choose one email signature when starting an email conversation or replying for the first time, and another email signature for replies.

Kind regards, 
Bo Thygesen