Right-click to save canvas as jpg only

I'm using this to capture images as canvas from a video URL:

var videoId = 'video';
var scaleFactor = 0.55; // increase or decrease size
var snapshots = []; 
/**
 * Captures a image frame from the provided video element.
 *
 * @param {Video} video HTML5 video element from where the image frame will be captured.
 * @param {Number} scaleFactor Factor to scale the canvas element that will be return. This is an optional parameter.
 *
 * @return {Canvas}
 */

function capture(video, scaleFactor) {
    if(scaleFactor == null){
        scaleFactor = 1;
    }

    var w = video.videoWidth * scaleFactor;
    var h = video.videoHeight * scaleFactor;
    var canvas = document.createElement('canvas');
        canvas.width  = w;
        canvas.height = h;
    var ctx = canvas.getContext('2d');
        ctx.drawImage(video, 0, 0, w, h);
    var uniq = 'img_' + (new Date()).getTime();
    canvas.setAttribute('id', uniq);

  return canvas ;

}

/**
 * Invokes the <code>capture</code> function and attaches the canvas element to the DOM.
 */
function shoot(){
    var video  = document.getElementById(videoId);
    var output = document.getElementById('output');
    var canvas = capture(video, scaleFactor);

    snapshots.unshift(canvas);
    output.innerHTML = '' ;

    for(var i=0; i<10; i++){
       output.appendChild(snapshots[i]);

    }
}

The problems:

1 - Currently, browsers treat <canvas> like they they treat a <div> and this make it impossible to save any generated canvas as an image because when I right-click on each and everyone, it always opens the windows dialog here I have to choose Save image as....

2 - The windows right-click dialog always opens by default the option to save image as transfer.png and I would like to save the image with their ID attribute (var uniq) and a jpg extension.

Example:

The output canvas is like this: <canvas width="352" height="198" id="img_1575807516362"></canvas>.

I want the right-click to open the windows dialog offering to save image like this img_1575807516362.jpg.

Alternatively, it would be nice tho have a download button for each canvas to export the canvas as an image like this transfer.jpg.

Is it possible with this code?