Detecting image sizes

If we know what kind of image we are facing, detecting the resolution is usually a matter of reading it from the image header.

For most image types, this is relatively simple, and as we can use imghdr to guess the right image type, we can then read the right part of the header, according to the detected type, to extract the size portion.

How to do it...

Once imghdr detects the image type, we can read the content of the header with the struct module:

import imghdr
import struct
import os
from pathlib import Path


class ImageReader:
    @classmethod
    def get_size(cls, f):    
        requires_close = False
        if isinstance(f, (str, getattr(os, 'PathLike', str))):
            f = open...