Photograph Resize

I use PS 7:

Open PS. 
Click on the "image" menu item
Click on "Image size"

At this point, you should see a modal popup that has the width and height of your photo.  Make sure "Constrain proportion" checkbox is checked.  To confirm, change either attribute of your image and confirm that when you change one, the other automatically changes as well.  If you don't check the "constrain proportions" checkbox, changing one attribute won't change the other which implies your photo will be out-of-wack.

Once done, click "ok" and you photo, complete with updated proportions should be in front of you.

later

I now have PS in front of me and have modified my post above.

Thanks, and sorry for any inconveniences.