Created attachment 159928 [details] The difference between folders with previews and folders without previews SUMMARY When folder preview is enabled, directories with previews look different than empty ones. It looks like it's using an icon from bigger size and then downscaling it, making it blurry. See attachment STEPS TO REPRODUCE 1. Use icon themes like Chicago95 or SE98 with icon size set to 48 2. Have folder previews enabled OBSERVED RESULT Folders without previews look as they should, folders with previews are blurry EXPECTED RESULT Folders with previews should not be blurry SOFTWARE/OS VERSIONS Linux/KDE Plasma: (available in About System) KDE Plasma Version: 5.27.6 KDE Frameworks Version: 5.107.0 Qt Version: 5.15.10 ADDITIONAL INFORMATION Another icon theme issue, not just dolphin specific, is that the icon themes with both pngs and svgs (like Chicago95) don't look right. In dolphin (also tested in pcmanfm-qt) PNGs are prioritized, so if the icon theme has a 48x48 directory with .png files and a scalable directory with .svg files, the 48x48 pngs are used and svgs are ignored. You can see this if you set the toolbar icon size to 64x64. Plasma panel on the other hand prioritizes svgs for all sizes, ignoring pngs. I don't know where exactly I should post this, so I'll just leave it here, maybe it's a Qt issue, I'm not sure.
Created attachment 160601 [details] 22pixels icons With 16 and 22pixels icons, it seems folders that can show previews use different icons than others.
*** This bug has been marked as a duplicate of bug 387154 ***