Not possible to zoom in.
How did you get the image size? If you do not know the original then it is just a guess.
For an RGB image, you might be able to narrow it down a little. Dividefile size by 3 (channels) gives the product of the width x height. That might rule out common sizes as multiples of 100 or 64/128/256.
Since it is just data you can divide the file up into parts, easy enough in Linux, don't know about Windows.
That might get you a part image that you can at least fiddle with size values.
Sort of example, just the bottom quarter: https://i.imgur.com/hVYZAiF.jpg
How did you get the image size? If you do not know the original then it is just a guess.
For an RGB image, you might be able to narrow it down a little. Dividefile size by 3 (channels) gives the product of the width x height. That might rule out common sizes as multiples of 100 or 64/128/256.
Since it is just data you can divide the file up into parts, easy enough in Linux, don't know about Windows.
That might get you a part image that you can at least fiddle with size values.
Sort of example, just the bottom quarter: https://i.imgur.com/hVYZAiF.jpg