There is another small tool called "ATR Image Size Corrector" from Christian Wyk. The program is german-only, but that doesn't matter, you can figure it out how it works... PC windows program.
There are only 4 options
"Einzelne Datei korrigieren" means "correct one single file",
"Verzeichnis korrigieren" means "correct folder",
"XFD>ATR konvertieren" means "convert XFD>ATR" and
"Sortieren" means "sort".
Ah yes, and the buttons:
"Datei wählen" -> "choose file",
"Verzeichnis wählen" -> "choose folder",
"schliessen" -> "end",
"Quelle..." -> "source...",
"Ziel..." -> "target..."
Attachment:
ATRImageCorrector.zip