Content load on the same pop window

hello flash experts

once a button is clicked a pop-up window appear.
i have different size pop-up windows.

what i want is to open separate pop-up window. it works fine if the user close the pop-up window before opening a new pop-up window. however, when the user decide not to close it and try to open a different pop-up window, the prolem occure.

for example, the first pop-up window is 300x300px. then you clicked on another button to open a larger image (500x500px). the image just load onto the same pop-up window and my larger image is cut off. do i make sense?

can anyone help me?