Necessary to add the height and width to the img

Is it necessary to add the height and width to the img src tag?

Yes. Adding the height and width attributes to your IMG SRC HTML tag allows the browser to properly size the images as the page is loading. Without these values the browser will not know how to properly size each image and will only be able to determine the size of the image after it has been loaded.

You'll notice web pages that do not have their image dimensions specified, since the overall size and layout of the page will change as the page is loaded. This will often confuse the user and/or distract them as they are trying to read the content on the page.