JSFiddle - React, Tailwind, and code Playground

JavaScript

handleOpenedFile('http://www.electricscotland.com/pictures/images/views30.jpg');

function handleOpenedFile(fullPath, blobData) {
            var image = new Image();
            image.src = fullPath; //path to image
            image.onload = function () {
                var resized = resizeMe(image); // send it to canvas
                //Do stuff with the DataURL returned from resizeMe()
            };
    }

function resizeMe(img) {

        var canvas = document.createElement('canvas');
        var width = Math.round(img.width / 2);
        var height = Math.round(img.height / 2);
        canvas.width = width;
        canvas.height = height;
        var ctx = canvas.getContext("2d");
        document.body.appendChild(canvas);
        ctx.drawImage(img, 0, 0, width, height);
        return canvas.toDataURL("image/jpeg", 0.8);
    }