To work faster in Photoshop without damaging the image, select the Use Pixel Doubling option in the Photoshop preferences. The Use Pixel Doubling option works when you move image information within a Photoshop document. Let's say you select and move an area of an open image. Normally, the information you see displayed as you click and drag is at the same resolution as the original image. Displaying a full-resolution copy of the information requires Photoshop to use memory and processor time. In high-resolution images, this can make moving large areas of a graphic a slow and tedious job.
If Use Pixel Doubling is selected, Photoshop reduces the resolution of the moved image and restores the image to full resolution when you complete the move. You work faster without compromising the quality of the image.