diff --git a/pixelocr/gui/ocrengine.py b/pixelocr/gui/ocrengine.py
index 2dd2d54..6455488 100644
--- a/pixelocr/gui/ocrengine.py
+++ b/pixelocr/gui/ocrengine.py
@@ -36,7 +36,7 @@ class OCREngine(QThread):
     def __init__(self, dirname):
         super().__init__()
         self.dirname = dirname
-        self.filenames = glob(path.join(dirname, '*.png'))
+        self.filenames = sorted(glob(path.join(dirname, '*.png')))
         self.glyphdb = GlyphDB(path.join(self.dirname, 'glyphdb.pickle'))
         self.help_queue = Queue()