toDataURL.js

function toDataURL (src, callback, outputFormat) {
    const img = new Image()
    img.crossOrigin = 'Anonymous'
    img.onload = function () {
        const canvas = document.createElement('canvas')
        const ctx = canvas.getContext('2d')
        canvas.height = this.naturalHeight
        canvas.width = this.naturalWidth
        ctx.drawImage(this, 0, 0)
        const dataURL = canvas.toDataURL(outputFormat)
        callback(dataURL)
        console.log('toDataURL', 'DONE', dataURL.length)
    }
    img.src = src
    if (img.complete || img.complete === undefined) {
        img.src = 'data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///ywAAAAAAQABAAACAUwAOw=='
        img.src = src
    }
}

use it like toDataURL('s/czg.svg', copy) in browser F12 devtools. It copies the base64 encoded image to the clipboard.