Album covers not displayed in a Subsonic API client (DSub)

[Bomfunk]

I couldn't find an existing issue for this, and I'm not sure what's causing it. But here is the symptom:
When browsing the albums in a list in DSub, the cover pictures are visible. But once I enter an album the UI acts like there's no picture (just displays the name).
Same happens when anything is playing - there's never a cover displayed now.

This worked fine before, but I haven't noticed which version has broken this, unfortunately, as I haven't used LMS for some time.

[Bomfunk]

After a closer look it seems that the covers work well for some of the albums, but not for the others. I couldn't figure out yet what's the difference between them. They all seem to work fine in the LMS UI itself, but not in DSub.

I usually remove the covers from all the mp3's and only keep cover.jpg in each album folder.

If I can provide some information to help troubleshoot this - please let me know.

[epoupon]

Hello! Did you try with another client like Ultrasonic?

[Bomfunk]

Yes, just tried that now - Ultrasonic shows the same behavior.

[epoupon]

So you confirm there is no embedded cover for the whole album?
Is the cover file special? Format, size, maybe?

[Bomfunk]

I think I have found the difference - indeed, the cover image is only shown when it's embedded in the music files themselves, but isn't working when it's simply a cover.jpg in the directory. I thought I don't have any images embedded, I normally remove them, but some slipped.
The format of the 'cover.jpg' file is the same everywhere and is, well, a jpg. The embedded ones I could spot are png, but I don't think format is the culprit considering the above.

Again, covers are shown when browsing the albums, but not when I enter them or play a song from them, unless they're embedded.

[epoupon]

Good catch!
Well, it looks like we should return the cover of the album for each track, if no embedded cover is found.