knofte

Gravatar Alt Tags is a WordPress plugin designed to improve accessibility and SEO on your website. It automatically adds descriptive alt tags to Gravatar images based on the user’s display name. This feature aids screen readers and search engines by providing meaningful descriptions for Gravatar images.

Alt-Tags-for-Gravatar

A simple WordPress plugin that enhances website accessibility and SEO by adding alt tags to Gravatar images for post authors and commenters.

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

Alt-Tags-for-Gravatar vs Title like Alt