Resize JPG in PSD file in a certain size

Will the resize you need to do be the same aspect ratio as the image being populated into the PSD.  Will and pespective need to be added to the resized image.

If you drag an image into a Document and while dragging it in hold the shift key when you drop the image the layer added will be centered,   you can then use Ctrl+T free transfom hold down shift + Alt and drag a corner to resize the image it will resize from the center and constrain the resize to the image's aspect ratio.