What did you do?

I tried to open this large TIF file with Pillow 6.0.0 in the following way:
image = Image.open(input_path)

What did you expect to happen?

No exception. And later I want to able to create thumbnails from the image.

What actually happened?

An exception was thrown:
OSError: cannot identify image file '/code/assets/lib/tests/test_data/alp-1978-big-tif.tif'

What are your OS, Python and Pillow versions?

• OS: Inside a Docker container, Debian stretch 9
• Python: Python 3.6.7
• Pillow: 6.0.0

This is possibly related to #3372