What is being advocated here for is to duplicate the alt= and title= elements on the <img> tag but I remember reading that this is not recommended a bunch of places. For example
Relying on the title attribute is currently discouraged as many user agents do not expose the attribute in an accessible manner as required by this specification (e.g. requiring a pointing device such as a mouse to cause a tooltip to appear, which excludes keyboard-only users and touch-only users, such as anyone with a modern phone or tablet).
alt is the important attribute, title is kinda.. honestly irrelevant in today’s mostly-smartphone world?