Not sure this is a 100% Lightning question, but it is related to the new Send email from Sales Cloud via Gmail feature. The feature is super cool. The challenge I've run into is that we use both images in the signature, which I was able to figure out,  but also different fonts/bold or not, etc for text. If I paste the entire HTML marketing gave me, I get the error You can't use more than 1,333 characters.. It would be nice if the email signature supported rich text, but I don't see that even as an idea pending....