Checks whether or not an image is a tracking pixel
@param {Node} image - DOM node for an img
@returns {boolean} isTrackingPixel - returns true if image is probably a tracking pixel
function isTrackingPixel( image ) {
	if ( ! image || ! image.src ) {
		return false;
	}

	const edgeLength = image.height + image.width;
	return edgeLength === 1 || edgeLength === 2;
}