diff --git a/build.out b/build.out
new file mode 100644
index 000000000000..e69de29bb2d1
diff --git a/lib/matplotlib/axes/_axes.py b/lib/matplotlib/axes/_axes.py
index c55f77811859..c7b814ab024a 100644
--- a/lib/matplotlib/axes/_axes.py
+++ b/lib/matplotlib/axes/_axes.py
@@ -5869,6 +5869,7 @@ def imshow(self, X, cmap=None, norm=None, *, aspect=None,
         `~matplotlib.pyplot.imshow` expects RGB images adopting the straight
         (unassociated) alpha representation.
         """
+
         im = mimage.AxesImage(self, cmap=cmap, norm=norm, colorizer=colorizer,
                               interpolation=interpolation, origin=origin,
                               extent=extent, filternorm=filternorm,
diff --git a/lib/matplotlib/image.py b/lib/matplotlib/image.py
index 53ea452f4c84..2466ae9eaa0f 100644
--- a/lib/matplotlib/image.py
+++ b/lib/matplotlib/image.py
@@ -28,6 +28,7 @@
     Affine2D, BboxBase, Bbox, BboxTransform, BboxTransformTo,
     IdentityTransform, TransformedBbox)
 
+
 _log = logging.getLogger(__name__)
 
 # map interpolation strings to module constants
@@ -1093,6 +1094,7 @@ def set_data(self, x, y, A):
         """
         Set the grid for the pixel centers, and the pixel values.
 
+
         Parameters
         ----------
         x, y : 1D array-like
@@ -1582,6 +1584,10 @@ def imsave(fname, arr, vmin=None, vmax=None, cmap=None, format=None,
             _api.check_in_list(('upper', 'lower'), origin=origin)
         if origin == "lower":
             arr = arr[::-1]
+
+        if (isinstance(arr, list)):
+            arr = np.asarray(arr, dtype=np.uint8)
+
         if (isinstance(arr, memoryview) and arr.format == "B"
                 and arr.ndim == 3 and arr.shape[-1] == 4):
             # Such an ``arr`` would also be handled fine by sm.to_rgba below
@@ -1630,6 +1636,7 @@ def imsave(fname, arr, vmin=None, vmax=None, cmap=None, format=None,
             background = PIL.Image.new("RGB", pil_shape, color)
             background.paste(image, image)
             image = background
+
         pil_kwargs.setdefault("format", format)
         pil_kwargs.setdefault("dpi", (dpi, dpi))
         image.save(fname, **pil_kwargs)
diff --git a/lib/matplotlib/tests/test_image.py b/lib/matplotlib/tests/test_image.py
index 24a0ab929bbf..b02d005bb841 100644
--- a/lib/matplotlib/tests/test_image.py
+++ b/lib/matplotlib/tests/test_image.py
@@ -197,6 +197,25 @@ def test_imsave_fspath(fmt):
     plt.imsave(Path(os.devnull), np.array([[0, 1]]), format=fmt)
 
 
+def test_imsave_python_vanilla_list():
+    # Initializing RGBA data
+    # Instead of testing numpy array, use python list
+    input_img = [
+        [[255, 0, 0, 1], [0, 255, 0, 1], [0, 0, 255, 1]],
+        [[0, 255, 0, 1], [0, 255, 0, 1], [0, 0, 0, 1]],
+        [[0, 0, 255, 1], [0, 0, 255, 1], [0, 0, 0, 1]]
+    ]
+    buff = io.BytesIO()
+    plt.imsave(buff, input_img, format="png")
+    buff.seek(0)
+    read_img = plt.imread(buff)
+
+    # Need to multiply by 255 to adjust for normalization in imread()
+    read_img = (255*read_img).astype('uint8')
+
+    assert_array_equal(np.array(input_img), read_img)
+
+
 def test_imsave_color_alpha():
     # Test that imsave accept arrays with ndim=3 where the third dimension is
     # color and alpha without raising any exceptions, and that the data is