Hi BigD, I don't have PSE but I believe it would be the same. Click the layer with the photo you want to resize. Go to edit>free transform. Then you should get a transformation tool that is around your photo. Go to one of the corners while holding the shift key and make it larger or smaller. After your done click the check mark on the top of the pse toolbar. If you made a bobo click the "O" with the "/" through it. Then just start over.
Another thing I like to use if the rectangle selection marquee. Select the area you want to keep by drawing a rectangle around it. Click selections>inverse (located on the toolbar.) then delete. Then you can resize it bigger or smaller or keep it the way it is.
HTH's
