Image data of dtype <U15 cannot be converted to float

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-6-df9959733b9a> in <module>
      1 my_img = PIL.Image.open(img)
----> 2 plt.imshow(img)

/scratch3/venv/djrn/lib/python3.8/site-packages/matplotlib/pyplot.py in imshow(X, cmap, norm, aspect, interpolation, alpha, vmin, vmax, origin, extent, filternorm, filterrad, resample, url, data, **kwargs)
   2722         filternorm=True, filterrad=4.0, resample=None, url=None,
   2723         data=None, **kwargs):
-> 2724     __ret = gca().imshow(
   2725         X, cmap=cmap, norm=norm, aspect=aspect,
   2726         interpolation=interpolation, alpha=alpha, vmin=vmin,

/scratch3/venv/djrn/lib/python3.8/site-packages/matplotlib/__init__.py in inner(ax, data, *args, **kwargs)
   1436     def inner(ax, *args, data=None, **kwargs):
   1437         if data is None:
-> 1438             return func(ax, *map(sanitize_sequence, args), **kwargs)
   1439
   1440         bound = new_sig.bind(ax, *args, **kwargs)

/scratch3/venv/djrn/lib/python3.8/site-packages/matplotlib/axes/_axes.py in imshow(self, X, cmap, norm, aspect, interpolation, alpha, vmin, vmax, origin, extent, filternorm, filterrad, resample, url, **kwargs)
   5521                               resample=resample, **kwargs)
   5522
-> 5523         im.set_data(X)
   5524         im.set_alpha(alpha)
   5525         if im.get_clip_path() is None:

/scratch3/venv/djrn/lib/python3.8/site-packages/matplotlib/image.py in set_data(self, A)
    698         if (self._A.dtype != np.uint8 and
    699                 not np.can_cast(self._A.dtype, float, "same_kind")):
--> 700             raise TypeError("Image data of dtype {} cannot be converted to "
    701                             "float".format(self._A.dtype))
    702

TypeError: Image data of dtype <U15 cannot be converted to float