JSFiddle - React, Tailwind, and code Playground

by Roger Ramos

HTML

<input type="file"/>
 <img id="testImg" src="#" alt="your image" />

CSS

#testImg{position:absolute;left=-9999px;top:-9999px}

JavaScript

function getImgSize(input) {

    if (input.files && input.files[0]) {
        var reader = new FileReader();

        reader.onload = function (e) {
            $('#testImg').attr('src', e.target.result);
        }

        reader.readAsDataURL(input.files[0]);
    }
}

$('#testImg').on('load',function(){
                alert($(this).width()+'*'+$(this).height());
            })

$("input").change(function(){
    getImgSize(this);
});