I’m using Mailchimp and I can’t view images in my newsletter
The plugin works with Mailchimp very well, it is used on thousands of sites with Mailchimp RSS campaigns, so no worries, we can get Mailchimp issues worked out.
The common short answer is that the Mailchimp preview does not like responsive image code added by WordPress (not by our plugin), so the images don't show in Preview (show as broken images), you could ignore that but know they will work fine when the email is sent out; use the test email to see how things will really look. Happily, the Premium version of our plugin does offer an option to disable the responsive image code allowing them to display in Mailchimp's preview.
A longer, more in-depth trouble-shooting answer:
We always start with the raw feed... If you do see images in your raw feed, the plugin is working great... Your raw feed is usually at yourwebsite.com/feed/ but adjust that URL according to your blog post URLs.