Error processing images in AMP

I am seeing the following warnings:

Notice: Undefined offset: 1 in .../administrator/components/com_easyblog/includes/image/image.php on line 520

			preg_match('/src="([^"]+)"/', $image, $src);

			

			$url = $src[1];

In many cases, this preg_match returns no array, so $src is empty. Attempting to index into [1] thus fails. Here's the tag on an image that's not being converted to amp-img. It is found in the outer regex, but not the inner. Could it be that the img tag has a class before the src?

<img class='calloutplanet' src='https://www.retrograde.today/images/planetsretro/mars.png' alt='Mars' />