Error generating thumbnail

Error creating thumbnail: /bin/bash: warning: setlocale: LC_ALL: cannot change locale (en_US.utf8) convert: unable to open image `/var/www/public/w/images/5/51/Antonio_de_Pereda_-_El_sueo_del_caballero_-_Google_Art_Project.jpg': No such file or directory @ error/blob.c/OpenBlob/2924. convert: no images defined `/var/www/public/w/images/temp/transform_0ba5244a0e47.jpg' @ error/convert.c/ConvertImageCommand/3229. Error code: 1