Simplification.

[podgorskiy]

BTW, if you need to read image size without decoding the whole jpeg, use PIL. It reads file header first and never reads the body unless you access the data.
CV2 is forced to return numpy array and will decode the whole file.

    from PIL import Image

    img = Image.open('some path')
    w, h = img.size

[gidoretto]

Pillow does not do that?

PIL is kind of old.

[podgorskiy]

@gidoretto, sure I'm talking about Pillow, but the package is still called PIL