1) With your two page spread open go ahead and duplicate your document:
Image --> Duplicate (In Elements you will go to File-->Duplicate). I do this just in case something would go terribly wrong ;)
2)Choose Image --> Canvas Size : Change the width to 1/2 of the original size. (So if you have as 16" spread you will change it to 8".) Click on the LEFT anchor point as shown below.
3) Choose ok and save your page as a .jpg
4) In your History pallete step all the way back so that your page is once again its original size. Choose Image -->Canvas Size and enter the same dimensions but this time click on the right anchor point.
