The results are in! Thank you for those that reported what you saw in your app of choice.
I put different images in different places.
I put a Green logo image in the ID3 tags (embedded in the mp3 file), A Blue logo image in the RSS image ( Called “iTunes image” in the item level of the RSS feed) A Green and blue imgage in the body of the post (Featured image) and the feed has the normal Orange logo image for the overall podcast artwork.
Here is what we have found so far: (will be updated as I get more info)
This is from Episode 129
Apple Podcasts (on Mac and IOS): No episode artwork shown (other than directory search under episodes results which show the RSS image)
iTunes desktop software (on older Macs and Windows): No episode artwork shown (other than directory search under episodes results which show the RSS image)
Antenna Pod (Android): Shows artwork from the post (Weirdly) and then in the player shows the RSS image
Podbean Player App (Android): Main show artwork. No episode artwork shown.
Himalaya (Android and IOS): RSS image shown
Spreaker Player App: (Android and IOS): RSS Image Shown
Google Podcasts (Android and Web): Main podcast Image Shown everywhere. No Episode image
Pocket Casts (Android, IOS, Web): Main Podcast Image shown. Strangely, it does show featured image posted in the post as well but only the main image in the player.
Podcast Republic (Android): RSS image shown
Podcast Addict (Android): RSS image shown. Also image from the body of the post shown.
Beyond Pod (Android): Featured image shown in the episode list and the main podcast image shown in the player
Overcast (IOS): ID3 tag image shown in the player, if you click show image in the shownotes, the featured image will show
Updated! Spotify (IOS, Android, Windows, Mac, Web): RSS image on all when playing the episode *** Also RSS image in the embedded player form Spotify (Thanks James!)
Stitcher (IOS, Android, Web): Only the main image shows everywhere
Tunein Radio (IOS, Android, Web): REALLY Old main image only (they didn’t update my image for over a year!)
Pandora (IOS, Android, Web): RSS image shown
iHeart Radio (IOS, Android, Web): Main artwork shows everywhere
Deezer (IOS, Android, Web): Main artwork shows everywhere
Skipcast (IOS): Main artwork shows everywhere
CastBox (IOS, Android): Featured image in post shows everywhere
Blubrry Directory (Web): Main Image only
TechPodcasts.com Directory: (Web): Main image only
New! iCatcher (IOS): Uses the Main image for streaming but the ID3 image for downloaded episodes. (Thanks Jeremy!)
New! Player.FM (IOS, Android): Uses RSS image in the player and the featured image in the listing for the episode (Thanks Michael!)
New! Podchaser.com (web): Uses RSS image in the player and the featured image in the listing for the episode. (Thanks Dave!)
If you have seen anything different than this list or have another player I didn’t list, let me know. email@example.com
Bottom line. If you are going to put in an episode image. The best places to do that is in the post (featured image or the first image in the post) and the RSS (iTunes) image at the episode level. ID3 tag image only shows up in 2 places. Overcast and “iTunes” desktop (which is dead other than windows and older mac OS). Maybe still worth doing in the ID3 if it’s not too much work.