Only fix generated thumbnails
Only fix generated thumbnails

There was a bug where we would process all files even though they had not been generated by Preview
setnes/galleryplus,interfasys/galleryplus,tahaalibra/gallery,leftees/galleryplus,interfasys/galleryplus,imjalpreet/gallery,owncloud/gallery,patman15/galleryplus,setnes/gallery,owncloud/gallery,IATkachenko/gallery,viraj96/gallery,IATkachenko/gallery,viraj96/gallery,owncloud/galleryplus,desaintmartin/gallery,leftees/galleryplus,setnes/gallery,owncloud/galleryplus,setnes/galleryplus,imjalpreet/gallery,tahaalibra/gallery,interfasys/galleryplus,owncloud/galleryplus,IATkachenko/gallery,imjalpreet/gallery,patman15/galleryplus,patman15/galleryplus,desaintmartin/gallery,efueger/galleryplus,leftees/galleryplus,desaintmartin/gallery,tahaalibra/gallery,owncloud/gallery,viraj96/gallery,setnes/galleryplus,efueger/galleryplus,setnes/gallery