chroniceel added a comment.
Okay, removing the line appears to have a similar effect to what I already did. I checked over on the imagecreator.cpp file, which appears to handle the thumbnailing of most other image types, and despite also using a QImageReader object, it does not call setQuality. My best guess is that QImageReader uses a sane value by default, and the imagecreator.cpp class lets that ride, ergo good thumbnails. I have no clue why this was set here, nor why it was set to 0. REPOSITORY R320 KIO Extras REVISION DETAIL https://phabricator.kde.org/D26648 To: chroniceel, broulik, #frameworks, #vdg Cc: bruns, ngraham, kde-frameworks-devel, kfm-devel, pberestov, iasensio, fprice, LeGast00n, MrPepe, fbampaloukas, alexde, GB_2, Codezela, feverfew, meven, michaelh, spoorun, navarromorales, firef, andrebarros, emmanuelp, mikesomov