How do you get the alt attribute values of images?

Hello

I would like to get the alt attribute value of each image registered using Dynamic Featured Image. I registered two images in the static home page and managed to display them using the code below but failed to display their alt attribute values:

if(class_exists('Dynamic_Featured_Image')){
	global $dynamic_featured_image;
	$featured_images = $dynamic_featured_image->get_featured_images(get_the_ID);
	$featured_image_alt =
	$dynamic_featured_image->get_image_alt_by_id(get_the_ID);
	$image0 = $featured_images[0];
	$image1 = $featured_images[1];
	$imageAlt0 = $featured_image_alt[0];
	$imageAlt1 = $featured_image_alt[1];
	echo '<img src="'.$image0['full'].' " alt="'.$imageAlt0.'">';
}

Replacing get_image_alt_by_id() with get_image_alt() returns the empty value too, so I guess I’m not following the descriptions given in the plugin’s GitHub page:

https://github.com/ankitpokhrel/Dynamic-Featured-Image/wiki/API#8-get_image_alt-image_url-

Please someone help me display the alt attribute values.

Thanks for reading this.