Simplify cropping images to standard photo dimensions, to prepare them for digital printing. As shown in the 'Photo print sizes' Wikipedia article, aspect ratios vary with size, so simply resizing is insufficient. We’d like to be able to select from

Simplify cropping images to standard photo dimensions, to prepare them for digital printing. As shown in the 'Photo print sizes' Wikipedia article, aspect ratios vary with size, so simply resizing is insufficient. We’d like to be able to select from a list of 4″×6″, 5″×7″, etc; and then be able to slide that sized cropping-frame around the image on the screen to preview the effect. Thanks!