ImageField accessing height or width and then data results in "I/O operation on closed file"

[ROsborne]

If you have a simple model with an ImageField, the following code will fail with a "I/O operation on closed file":

instance = MyClass.objects.get(...)
w = instance.image.width
h = instance.image.height
original = Image.open(instance.image)

The work around is to reopen the file:

instance = MyClass.objects.get(...)
w = instance.image.width
h = instance.image.height
instance.image.open()
original = Image.open(instance.image)

Note this is different than the issue of the 2nd read() returning empty strings for two reasons:

1. You can not seek(0), the file is closed.
2. Needing to reopen in this case is unexpected.