patch: Greyscale image prediction condition.

deepface/models/Demography.py

@@ -38,14 +38,15 @@ def _predict_internal(self, img_batch: np.ndarray) -> np.ndarray:
         if not self.model_name: # Check if called from derived class
             raise NotImplementedError("no model selected")
         assert img_batch.ndim == 4, "expected 4-dimensional tensor input"
-        # Single image
-        if img_batch.shape[0] == 1:
+
+        if img_batch.shape[-1] != 3: # Handle grayscale image, check last dimension.
             # Check if grayscale by checking last dimension, if not 3, it is grayscale.
-            if img_batch.shape[-1] != 3:
-                # Remove batch dimension
-                img_batch = img_batch.squeeze(0)
+            img_batch = img_batch.squeeze(0) # Remove batch dimension
+
+        if img_batch.shape[0] == 1: # Single image
             # Predict with legacy method.
             return self.model(img_batch, training=False).numpy()[0, :]
+
         # Batch of images
         # Predict with batch prediction
         return self.model.predict_on_batch(img_batch)