HTML emails need to be designed and coded in a certain way in order to display as intended and to be as optimised as possible to their purpose. I design and code emails using email best practice and give 3 drafts to choose from before developing and coding the final design for use in your email marketing platform, whether it's your own custom one or MailChimp for example. Often, emails are designed as if they are a poster. While they look great to you as an image, when they are actually sent to your recipients then they are likely to appear as a blank space. Images are often blocked by default in most email providers until the recipient unblocks them. If the email appears blank immediately then sometimes recipients may not unblock them and will just move on from the email. Emails need to quickly grab attention and encourage someone to do a particular action whether it's visiting your shop nearby or purchasing something online. Text should be used more so than images as this appears immediately.