Les Bessant

gashacon

WordPress 3.5 introduced a new feature – when images are inserted into posts, the title attribute is not included in the image tag. This was done with the best of intentions relating to accessibility, as documented on <a href="https://core.trac.wordpress.org/ticket/18984" rel="nofollow ugc">Trac</a>
Unfortunately, this causes problems for some Lightbox plugins, quite apart from stopping image tooltips from appearing.
This plugin hooks into the media_send_to_editor filter and inserts the image title into the html inserted into the post.
The original author, LesBessant, sadly passed away and in the meantime the original plugin was closed. I plan to keep the plugin up to date whenever an update breaks it.

IMG Title Restore

Restores the title attribute when images are inserted into posts

José Luis López

Automatically fills in the title, alt and description attributes of images when uploading.

JL Image Attributes

Automatically fills in the title, alt and description attributes of images when uploading.

IMG Title Restore vs JL Image Attributes