Create different description on non-thumbnail image

Hi

I couldn’t see this precise issue on the forum – I’d be really grateful for any comments

I’m running Hero theme from Themetrust, and using NEXTGen as the gallery plugin. All I’m trying to do is display a couple of words under each thumbnail in the gallery, then when each thumbnail is clicked on, and the larger image comes up, I want to have a 3 line description of the image in question. At the moment, I’m getting the description showing up under both the thumbnail and the larger image ( I entered the description through the Dashboard under the Alt & Title Text / Description field against each image)

Is there any way of displaying a short title under the thumbnail, then a fuller description under the expanded image?

Many thanks

J