Need help on Instances

I need some help in regards to Instances of objects or symbols.

Basically what I need to do is as follows:

I create a blank object or blank symbol called ImageObject that holds an initial image (just say, a image of a frog).

Then I obtain some passed variables from PHP/MySQL and if the results say there are two images or more to be displayed (just say, a lizard and a turtle), then Flash will create another instance of ImageObject, and change the initial image to the lizard image.

Then it makes another instance of ImageObject and changes that initial image to the turtle.

But when I change the image of the first duplicated ImageObject to the lizard, it changes the very first one into the lizard as well. So it looks like it will only display the one image on all of the instances.

Can someone help me out here?

Thanks