One way you can do it (but does not work that well) is click on the move tool and hit CTRL T, then hold down the shift and CTRL key. This method does not help to be precise, but the image quality seems to not change much. Alternatively when using the transform you can hold the CTRL key, but you will loose detail. One thing to note is that you should always work with bigger images. You can always make it smaller if it is too big and not loose quality, but resizing a small image to be larger is a big no because quality will always be lost. -LeFrog