Script Summary: Puts alt text or source filename in image title attribute, if title is empty.
A simple script for image title attributes.
If title tag is populated, it does nothing.
If title tag is empty and alt tag is populated, puts alt tag in title.
If alt and title tag are empty, puts the filename in alt and title.
Useful in Firefox to show alt text or filename as a tooltip pop-up for images where there is no title text.
Firefox (correctly) does not show alt text as a tooltip. I like image tooltips regardless of whether the page author designed it that way.
Modified from http://userscripts.org/scripts/show/30956