Podcast artwork shows in Apple Podcasts and iTunes but not on iPhone

Question

I submitted my first podcast to Apple Podcasts. The RSS feed has this tag for the icon:

<?xml version="1.0" encoding="UTF-8"?><rss xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:content="http://purl.org/rss/1.0/modules/content/" xmlns:atom="http://www.w3.org/2005/Atom" version="2.0" xmlns:itunes="http://www.itunes.com/dtds/podcast-1.0.dtd">
    <channel>
        <title><![CDATA[Ginja]]></title>
        <description><![CDATA[Um curso virtual que desenvolve a inteligência emocional nas crianças]]></description>
        <link>https://emocoes.org</link>
        <image>
            <url>http://emocoes.org/images/logo_podcast.png</url>
        ...

The artwork works, since I can see it on Apple Podcasts:

and on iTunes:

But syncing it on my iPhone 4S, I do not see the artwork when the podcast is playing:

nor when browsing the library:

The iOS version is 9.3.6.

How can I change the podcast feed or artwork to show on all iPhones?

Answer 1

One solution is to embed the artwork into each audio file. Command-line solutions include lame and ffmpeg, for example:

lame --ti /path/to/file.jpg audio.mp3
ffmpeg -i input.mp3 -i cover.jpg -map_metadata 0 -map 0 -map 1 output.mp3

See more at: https://unix.stackexchange.com/questions/84915/add-album-art-cover-to-mp3-ogg-file-from-command-line-in-batch-mode

You can also download dedicated software for this purpose, though I did not try it.

Either way, if you handle the low-level of podcast distribution, remember to update the length attribute to reflect the now larger file, or else the duration may be computed from the file size and display the wrong number.