Do you want to see the thumbnail image in your blog posts?
If yes, what you’re looking for is: the_post_thumbnail( $size, $attr )
Also, did you know that WordPress comes with a default thumbnail image size?
Replace $size with ‘thumbnail’, ‘medium’, ‘large’ or ‘full’ or go to Settings > Media to change the default sizes.
Are your email templates mobile ready?
A quick look over your send statistics should give you and idea of how many subscribers are using mobiles to consume your email data.
Remember, any links you include in your campaign should ideally have a mobile friendly version too – this way you’ll ensure that the conversion path is not dead in the water!