Does exactly what I wanted and outstanding support from the developer too!

Finally, a plugin that does exactly what it claims to do, with no fuss or bother. I wanted a simple text form in the Image Details dialog box for photo credits, and this plugin delivered.

Further to that, props to @pputzer, the developer of this plugin, for being helpful and super quick pushing out a fix (in a matter of hours!) when I discovered a slight bug in the plugin. Top notch!