I have a project in Angular and I generate a map image in canvas using OpenLayers, then I download it locally with the extension .png/.tiff using fileSaver. How can I add metadata to the downloaded file (blob) to include, for example, coordinates?

mapCanvas.toBlob(blob => {
        fileSaver.saveAs(blob, 'example.png');
      });

Tried with various npm exif libraries but they mainly have methods for reading.