how to import the html signature to mail app from outlook 2013

I've been trying to add html signature to mail app, but all my trials didn't succeed. all what I'm getting is the signature without pictures even though all the pictures are linked in the email signature, the steps that i've followed is that I've exported the email signature I was using in outlook 2013, created a signature in mail app, copied the html codes from the exported signature, and pasted under the "mime" code in the "mailsignature" and locked it, all what I'm getting is in the picture uploaded, how to solve this problem?