Since the first time you are about to create the podcast, you can change the featured image for both Podcast Show and Episode image on the Confirm page.
If you want to change the featured image for your existing podcast episode, do the following steps;
1. On the Show page (Dashboard/Shows/Your show’s name), select the Episode you wish to update its featured image.
2. You are now in the Episode Editor page. Click the Setting icon at the top right of the Episode Banner. The episode Settings window will appear.
3. You can now update the featured image and also other information about your episode such as Publish status, Title, Description, Web URL, Featured Image, Host name, turn on/off the explicit content, and remove an episode.
4. Click Save. Done!