convert an image into Base64 string using JavaScript
function getBase64Image(src, callback, outputFormat) {
const img = new Image();
img.crossOrigin = 'Anonymous';
img.onload = () => {
const canvas = document.createElement('canvas');
const ctx = canvas.getContext('2d');
let dataURL;
canvas.height = img.naturalHeight;
canvas.width = img.naturalWidth;
ctx.drawImage(img, 0, 0);
dataURL = canvas.toDataURL(outputFormat);
callback(dataURL);
};
img.src = src;
if (img.complete || img.complete === undefined) {
img.src = "data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///ywAAAAAAQABAAACAUwAOw==";
img.src = src;
}
}