diff --git a/alibi/datasets/default.py b/alibi/datasets/default.py
index 603d8f8b2..00b84d5be 100644
--- a/alibi/datasets/default.py
+++ b/alibi/datasets/default.py
@@ -142,7 +142,8 @@ def load_cats(target_size: tuple = (299, 299), return_X_y: bool = False) -> Unio
         # data
         img = tar.extractfile(member).read()  # type: ignore[union-attr]
         img = PIL.Image.open(BytesIO(img))
-        img = np.expand_dims(img.resize(target_size), axis=0)
+        img = np.array(img.resize(target_size))
+        img = np.expand_dims(img, axis=0)
         images.append(img)
 
         # labels
diff --git a/alibi/explainers/pd_variance.py b/alibi/explainers/pd_variance.py
index 44d7fcf36..1c69881d0 100644
--- a/alibi/explainers/pd_variance.py
+++ b/alibi/explainers/pd_variance.py
@@ -815,7 +815,7 @@ def plot_pd_variance(exp: Explanation,
                              f"Available values are: {exp.meta['params']['target_names']}.")
 
         if isinstance(target, numbers.Integral) \
-                and (target > len(exp.meta['params']['target_names'])):  # type: ignore[operator]
+                and (target > len(exp.meta['params']['target_names'])):
             raise IndexError(f"Target index out of range. Received {target}. "
                              f"The number of targets is {len(exp.meta['params']['target_names'])}.")
 
diff --git a/alibi/utils/visualization.py b/alibi/utils/visualization.py
index d60ad6965..bd5ac0602 100644
--- a/alibi/utils/visualization.py
+++ b/alibi/utils/visualization.py
@@ -196,6 +196,7 @@ def visualize_image_attr(
     heat_map = None
     # Show original image
     if ImageVisualizationMethod[method] == ImageVisualizationMethod.original_image:
+        assert original_image is not None
         plt_axis.imshow(original_image)
     else:
         # Choose appropriate signed attributions and normalize.