Gmail doesn’t render the Season/Series Premiere header images when using the “View entire message” option for long digest emails.
For example, here is what this weeks “All weekly TV show premieres” digest email looked like for me in Gmail when viewed inline in my inbox. The premiere headers are there.
Because the email is long I need to click the “View entire message” link at the bottom to view the whole thing and this is what it looks like. As you can see the Season/Series Premier header images are missing.
Edit: In case it’s relevant, this is when accessing Gmail in Firefox on macOS.