diff --git a/pixelocr/gui/__init__.py b/pixelocr/gui/__init__.py
index 343b5ef..8855975 100644
--- a/pixelocr/gui/__init__.py
+++ b/pixelocr/gui/__init__.py
@@ -42,7 +42,7 @@ def main():
     win = MainWindow()
     win.show()
 
-    ocr = OCREngine(sys.argv[1:])
+    ocr = OCREngine(sys.argv[1])
     ocr.pageChanged.connect(win.pageScene.setPage)
     ocr.unknownGlyph.connect(win.unknownGlyph)
     win.glyphEntered.connect(ocr.give_help)
diff --git a/pixelocr/gui/ocrengine.py b/pixelocr/gui/ocrengine.py
index 0d31da0..409d045 100644
--- a/pixelocr/gui/ocrengine.py
+++ b/pixelocr/gui/ocrengine.py
@@ -14,6 +14,8 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 
+from glob import glob
+from os import path
 from queue import Queue
 
 from PyQt4.QtCore import (
@@ -30,9 +32,9 @@ class OCREngine(QThread):
     unknownGlyph = signal([Glyph])
     pageChanged = signal([Page])
 
-    def __init__(self, filenames):
+    def __init__(self, dirname):
         super().__init__()
-        self.filenames = filenames
+        self.filenames = glob(path.join(dirname, '*.png'))
         self.chardb = {}
         self.help_queue = Queue()