Why images are better to be uploaded with the exact reaquired size

The logo on your website and the images should be uploaded with the exact required size, otherwise the browser will have to do it for you, and that is an extra request each time a page is openned, which affect the speed and your SEO process

If images are uploaded with a different size It ll also be an extra request each time an image is loaded on the user screen .. let that sink in for a moment

Note that the size i mean is the area of the image not the size of it on the hard desk