Cover art
Put an image in the library and name it:
[feed]
cover = "cover.jpg"Every publish re-normalizes it. The original file is never modified.
Why this is a whole subsystem
A non-compliant <itunes:image> produces no error anywhere. The feed still validates, the app shows its grey placeholder, and nothing in the chain tells you which of the rules you broke. Diagnosing that from a phone is miserable.
So earmark does not ask you for a compliant file. It makes one. Apple’s rules, which Castbox, Overcast, Pocket Casts and Spotify all follow:
- square, 1400×1400 minimum, 3000×3000 recommended
- JPEG or PNG, RGB; CMYK is rejected outright
- no transparency; a PNG with an alpha channel renders wrong
- under 512 KB
A logo exported for a README hits none of the last three: usually RGBA, often under 1400px, often over 512 KB. earmark flattens the alpha onto a solid background, pads to square, scales, and steps the JPEG quality down until the file is under the size ceiling. ffmpeg does all of it, so it costs no extra dependency.
Padded, never cropped
Non-square art is letterboxed onto a solid background. Cropping would silently eat part of a logo; letterboxing is a cosmetic result you can see and correct by supplying a square image.
cover versus image
| Key | Means |
|---|---|
cover |
A file in the library. earmark normalizes it on every publish and serves it from your base_url. |
image |
A URL to artwork hosted somewhere else. earmark passes it straight through and does nothing to it. |
image disables the cover pipeline rather than racing it: if both are set, image wins.
[feed]
image = "https://example.com/art/show.jpg"Changing it later
earmark feed --rebuildThat rewrites feed.xml and the cover from the current settings without touching any audio.
Be patient afterwards: artwork and show titles are cached aggressively by every podcast app, so a cover you add later can take hours to appear. Force-refresh the show, or unsubscribe and re-subscribe, if you can’t wait.