[web] Images with specific CORS headers give false negative

[walidvb]

I'm loading images from gravatar, and it seems that using the fetch API returns an error, even though the image would be correctly loaded by the browser.

I'll try and make a PR to address this, by changing the behaviour on web, along the lines of:

 const image = document.createElement('img');

  image.onload = setImageWorked;
  image.onerror = doUseFallback;
  image.referrerPolicy = 'no-referrer';
  image.src = src;

[avishayil]

Should be fixed with v1.0.8