Created attachment 130165 [details]
before and after adding a 'folder.jpg' image of the cover art to those album's directories.

SUMMARY
Under the 'Albums' tab, albums that only have the cover in the mp3's metadata will have horrible downscaling artifacts. However, if an album's directory contains a 'folder.jpg' of the cover, it will be downscaled properly.

STEPS TO REPRODUCE
1. Set Elisa to scan an album directory and make sure all the mp3's have the album cover in the metadata and that there is no folder.jpg of the album cover
2. Wait for Elisa to scan in the album
3. Open the "Albums" tab and look at the preview

OBSERVED RESULT
Album covers in the "Album" tab have bad artifacting when there is no 'folder.jpg' file of the cover in the folder of the album.

EXPECTED RESULT
Album covers taken from the mp3's metadata are scaled the same as album covers taken from a 'folder.jpg' file from within the album directory and are without artifacting.

SOFTWARE/OS VERSIONS
Linux: Manjaro
Kernel: 5.6.14-xanmod
KDE Plasma Version: 5.18.5
KDE Frameworks Version: 5.70.0
Qt Version: 5.15.0

ADDITIONAL NOTES
this artifacting issue also occurs in the 'Playlist', 'Frequently Played', 'Recently Played', and 'Tracks' tabs, but it's definitely most noticeable in the in 'Albums' tab as the preview is much larger there.