You can use the Free Transform command to change the size of photographs and selections.
Go to Image > Transform > Free Transform, or press Ctrl + t.
If you're resizing a photograph for printing, go to Image > Resize, instead.
Press Ctrl + Alt + t to transform a copy of the photograph or selection that you want to transform.
To change the size, or rescale, a photograph or selection, click a handle on an edge or corner, hold, and drag.
If you constrain the proportions, the aspect ratio remains the same.
Let's say you have a photograph that's 4 x 6 inches.
The aspect ratio is 1 to 1.5 (1:1.5).
If you change the width from 4 inches to 8 inches, Photoshop will automatically change the length to 12 inches, maintaining the 1:1.5 aspect ratio.
If you're using Photoshop Elements 5.0, select Constrain Proportions in the options bar, to constrain proportions.
If you press Alt, the change is made from the center out.
If you're using Photoshop Elements 4.0, press and hold Shift, to constrain proportions.
If you press Shift + Alt, the change is made from the center out.
If you open the Info palette, you can see the dimensions change.
To rotate, place the cursor in the area outside of the image.
The cursor will change to a curved two-sided arrow.
Press Shift and drag to constrain the rotation to 15° increments.
Distort stretches an item.
Press Ctrl, and drag any handle.
Skew slants an image vertically or horizontally.
Press Ctrl + Shift, and drag a handle in the middle of a side of the bounding box.
Press Ctrl + Alt + Shift, and drag a corner handle.
After making a change, click the check icon in the options bar, or press Return, to commit the change.
To cancel the change, click the circle-with-a line icon, or press Esc.