Thank you for reaching out to the Community! I apologize your email is not displaying as it should. Are you seeing this image size change in a test preview or in the editor itself? If this resize happens in a test preview, which email client and version are you using? Is this happening in more than one email client? All email campaigns in our system are mobile responsive so it will automatically resize itself depending on the screen and settings of the client it's being viewed through. So having these details along with any screenshots you may have will allow us to troubleshoot further.