problem with external image load and preloader

Hi,i'm new here and in flash action script .
i have a gallery with as2 ( attached ) but i want to manually address my button to open image from xml .
like :
buttom 1 on realease
load one image from xml on target movie clip on stage .
but i want to use movieclip loader to load all image first .
i can't understand how to do it with these code , and I'm very confused .
i don't want it to be sliding , just if i click on button ; external image load on target mc on stage .
i am new in action script , i see lots of sample but i have problem with each one , i cant understand how to modify them that way i want .
Please help .