Duplicate or double images?
- Two same images are used on the post, a featured image was set plus it was inserted at the top of the body.
- A conflicting plugin or WordPress theme also inserts feed images.
- You are using media tags and have not disabled featured images in plugin settings.
Use the RSS Image Checker tool to find out what images are pulled into the feed.
Note: The Image Checker will not detect images placed in the body content causing double images from "Featured Images Repeated In Body."
Featured Image Repeated in Body
Posts are showing a featured image and a body image.
By default the plugin uses the "featured image" (you would add these using a setting in the post). If the same image is also repeated in the body, and the email displays body content, you will see duplicate images. Remove the duplicate body image or use the Premium option to “use first image in body” to bypass the featured image.
When Deleting the Body Image is Not an Option
If deleting the body image impacts page display (the theme does not display a featured image on the web page) we have a solution. Use the Premium plugin option "feature first image" to send the first body image to the feed instead of a featured image.
Media Tag Repeated with Featured Image
If both a featured image and media tag are sent to the feed it could result in double images displaying in some services, like Mailchimp. Checkbox the setting "use only media tag images”.
Conflicting Plugins or Theme Setting
Our plugin passes one image to the RSS feed. Another plugin might be sending a second image to the feed. Go through other plugins to identify the conflict
In some cases the theme is sending a second image to the feed. Turn off the setting if that's an option. If not, check your theme's functions.php file for thumbnail RSS code. It can be a less obvious cause of duplicate images.
Read: Double post titles?