pop up window help

hi

Is anyone know that how to pop up a window after clicking on images.

i have made a page which contain the thumbnails of some images
each image has a diffrent size when i pop up a window by normal dreamwever extention it create a pop up window. and if i wants to pop up the blownup images into the same window i can't because the pop up is not resizing as per image size there for i can not pop up it in same window.

So is anyone knows the coad for the pop up window.....

please

abhi

http://www.guistuff.com/gen.shtml?pop