How to change the size of pictures in a javascript array for a slideshow?

The array is for a javascript slideshow and the array contains many different URL sources for pictures. How can the sizes of these pictures be changed so that all of them are the same height and width?

var photos=new Array()
var photoslink=new Array()
var which=0
//define images. You can have as many as you want:
photos[0]="http://ift.tt/1C8QWLR" 
photos[1]="http://ift.tt/1DVYvsU" 
photos[2]="http://ift.tt/1C8QWLW" 
//Specify whether images should be linked or not (1=linked)
var linkornot=0
//Set corresponding URLs for above images. Define ONLY if variable linkornot equals "1"
photoslink[0]="http://ift.tt/1C8QWLR"
photoslink[1]="http://ift.tt/1DVYvsU"
photoslink[2]="http://ift.tt/1C8QWLW"

How can the sizes of these pictures be changed so that all of them are the same height and width?