Since you can only ever send one version of your email signature, we have to make sure that the version you are sending is optimized for mobile.
Generally, email clients cannot include headers in the HTML, which removes the ability to create responsive email signatures, since the code needed to determine screen size is included in the header.
If you want your signature to look like its designed for mobile, there are some things you should do:
Include small images.
Images sent in email signatures to mobiles are not responsive, so the size of the image you send, is the size that will be received. Avoid the temptation to include really large logos or photos.
If you only include one image, our software will resize the image to be a good size for mobile screens. If you include two side by side images, make sure that they are maximum of 500px wide together (or 250px wide each).