Vadim Bogaiskov

Media file (image) does not contain field for title attribute, only for alt attribute.
Plugin add text into title attribute from alt attribute when image is inserted into post if title attribute is empty.
As alternative see plugin <a href="https://wordpress.org/plugins/restore-image-title" rel="ugc">‘Restore Image Title’</a> by Les Bessant. 
The ‘Restore Image Title’ inserted the post title into title attribute.

Title like Alt

Restores the title attribute from Alt attribute when images are inserted into posts

litefeel

Comments Avatar Lazyload at server side load replace the src property of img tag. It is relly lazyload. It was successfully checked by W3C. 
It is only lazyload comments avatar.
Related Links:
<ul>
<li><a href="https://www.litefeel.com/comments-avatar-lazyload/" title="Comments Avatar Lazyload Plugin for WordPress" rel="nofollow ugc">Plugin Homepage</a></li>
<li><a href="https://www.litefeel.com/" title="Author For Comments Avatar Lazyload Plugin" rel="nofollow ugc">Author Homepage</a></li>
<li><a href="https://github.com/lite3/comments-avatar-lazyload" title="On GitHub" rel="nofollow ugc">On GitHub</a></li>
</ul>

Comments Avatar Lazyload

Comments Avatar Lazyload at server side load replace the src property of img tag. It is relly lazyload. It was successfully checked by W3C.

Title like Alt vs Comments Avatar Lazyload