diff --git a/ppgan/apps/psgan_predictor.py b/ppgan/apps/psgan_predictor.py
index 46b59220ae5146786a73635ed2cb3f07e2ca432c..6bc58c4cb654b2c4bc199c40b6babd3a39ab85de 100644
--- a/ppgan/apps/psgan_predictor.py
+++ b/ppgan/apps/psgan_predictor.py
@@ -185,14 +185,22 @@ class PSGANPredictor(BasePredictor):
         inference = Inference(self.cfg, self.weight_path)
         postprocess = PostProcess(self.cfg)
 
-        source = Image.open(self.args.source_path).convert("RGB")
+        try:
+            source = Image.open(self.args.source_path).convert("RGB")
+        except IOError:
+            print("Error: {} is not exist".format(self.args.source_path))
+            sys.exit()
+
         reference_paths = list(Path(self.args.reference_dir).glob("*"))
+        if len(reference_paths) == 0:
+            print("Error: Can't find image file in {}.".format(
+                self.args.reference_dir))
+            sys.exit()
         np.random.shuffle(reference_paths)
         for reference_path in reference_paths:
             if not reference_path.is_file():
                 print(reference_path, "is not a valid file.")
                 continue
-
             reference = Image.open(reference_path).convert("RGB")
 
             # Transfer the psgan from reference to source.
diff --git a/requirments.txt b/requirments.txt
index 2816f6be1834c8b8dc10b9cd0a5de48ba1f9614c..6f6de9a77f009d0911ea1699d15ad6a4bf9852f5 100644
--- a/requirments.txt
+++ b/requirments.txt
@@ -4,3 +4,4 @@ scikit-image>=0.14.0
 scipy>=1.1.0
 opencv-python
 imageio-ffmpeg
+dlib