allow thumbnail.png to not exist

scanner/scanner.go

@@ -2,6 +2,7 @@ package scanner
 
 import (
 	"encoding/json"
+	"errors"
 	"fmt"
 	"os"
 	"path"
@@ -65,6 +66,9 @@ func ScanThumbnail(directory string) (string, int64, error) {
 	thumbnailPath := path.Join(directory, "thumbnail.png")
 	stat, err := os.Stat(thumbnailPath)
 	if err != nil {
+		if os.IsNotExist(err) {
+			return "", 0, err
+		}
 		return "", 0, err
 	}
 	if stat.IsDir() {