Convert dataURI to Blob so large images do not crash the browser. Based on: http://stackoverflow.com/questions/10412299 and http://stackoverflow.com/questions/6850276

dataURItoBlob.js

function dataURItoBlob(dataURI) {
    // convert base64 to raw binary data held in a string
    var byteString = atob(dataURI.split(',')[1]);

    // separate out the mime component
    var mimeString = dataURI.split(',')[0].split(':')[1].split(';')[0];

    // write the bytes of the string to an ArrayBuffer
    var arrayBuffer = new ArrayBuffer(byteString.length);
    var _ia = new Uint8Array(arrayBuffer);
    for (var i = 0; i < byteString.length; i++) {
        _ia[i] = byteString.charCodeAt(i);
    }

    var dataView = new DataView(arrayBuffer);
    var blob = new Blob([dataView], { type: mimeString });
    return blob;
}