| In Photoshop, open your photo in the program. Then go to Image - Image Size. The box that comes up will have full details on your photo size. The dimensions as well as the resolution will be shown. To make it 72 ppi, enter it in the resolution box. Be sure Constrain Proportions is checked to prevent distortion. You will also have to have Re-sample Image checked. You can also change the dimensions of the photo if you want, but if all you want is to put it at 72 ppi, (which is computer viewing resolution), just enter 72 in the resolution box and click the OK button.
steve | 
Linear Mode
