Restores WordPress default functionality prior to version 4.7 where image ALT attributes were automatically generated and put into the HTML code. The ALT attributes were generated from the Caption (if it exists) else from the Title (if it exists) of the image in the Media Library. This plugin utilises Titles in generating ALT text, but does not utilise Captions. The Title used by this plugin, is the main Title of the image as found in the Media Library, not the HTML TITLE attribute of the image (that is something else, which this plugin ignores).

Automatic image ALT attributes

This feature is a time saver for me as my site is image oriented.

Thanks

Automatically generates ALT attributes in image HTML. Restoring WordPress < 4.7 functionality.

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.

Automatic image ALT attributes vs Comments Avatar Lazyload