When you send out your newsletter via mailchimp it is best to have a combination of both images and text and the reason for this generally comes down to the settings a subscriber is using. If you have sent out your newsletter where the content is heavy with images whilst that may be great if a user’s email settings are to show images but it is also worth considering how the email would look if the images were turned off, would it still convey the same message?
The other aspect to consider if you are using a large amount of images in your newsletters is the amount of data that will consume and what device is the subscriber using to view it. As we are all leading busy lives it is now more common then ever that we are viewing a vast majority of content on tablets and mobiles and using mobile data. The best solution then is to have a mixture of images and text within your newsletter to address these potential issues.