Image description on clicking

I am wanting to have a slideshow of images in my database, which is easy enough to do with the slideshow plugin. What I would like to be able to do, is that when the current image is click it will display a popup, or a text box will become visable that will have information about what is in the image. For example a picture of a red wagon might have the description of the wagon, ‘a wagon, red in colour, with four wheels and a handle to pull it along with’.

Any ideas on how to achieve this?