Making caption compulsory

Hi all,

Been searching around and not found what I’m after. I would like to find a plugin that removes the caption showing up below an image, but also makes the caption compulsory instead of the title when you add an image. This way, all people who use my site will be forced to add valid ALT tags, instead of titles.

I found this plugin, which works great, but it doesn’t make the caption/ALT compulsory.