Hey!

Sorry for the late reply,

so finally I had to come with my own snippet, using the image title (from the media library) to populate the title attribute of the image,
something like this:

function my_function ($attr, $attachment, $size) {
$attr[‘title’] = get_the_title($attachment->ID); // get the Title of the attachment and use it as attribute
return $attr;
}
add_filter (‘wp_get_attachment_image_attributes’, ‘my_function’,10,3 );

(of course it depends on project context)