Thumbnails no longer saved in cache

[KonatoK]

Thumbnails generated by other thumbnailers like ffmpegthumbnailer are still saved there, but no the ones for regular image files done by pcmanfm. Other file managers don't have any issues with this so it is not a permissions issue, and pcmanfm can happily read the images generated by thunar, but it does not save its own in the thumbnail cache.