Display `Image` in notebook.

def show_image(img:Image, ax:plt.Axes=None, figsize:tuple=(3,3), hide_axis:bool=True, cmap:str='binary',
                alpha:float=None, **kwargs)->plt.Axes:
    "Display `Image` in notebook."
    if ax is None: fig,ax = plt.subplots(figsize=figsize)
    ax.imshow(image2np(img.data), cmap=cmap, alpha=alpha, **kwargs)
    if hide_axis: ax.axis('off')
    return ax