Photoshop CC: The Missing Manual

Content-Aware Scaling

Once in a blue moon, a software company adds a feature that works almost like magic. Adobe did exactly that back in CS4 with Content-Aware Scale (affectionately known in nerdy circles as CAS). CAS examines what’s in an image and intelligently adds or removes pixels from unimportant areas as you change the overall size of the image. The magic part? It knows enough to leave the important bits—such as people—unchanged. Think of web pages you’ve used that resize themselves smoothly and fluidly as you make the browser window bigger or smaller; now imagine doing the same thing with an image.

With this technology, Photoshop doesn’t squash or stretch the whole image; instead, the program adds or deletes chunks of, say, that big ol’ sky in the background or the grass in the foreground, leaving the important parts unscathed. A picture really is worth a thousand words when it comes to CAS, so take a peek at Figure 7-22 to see what this feature can do.

You can use CAS in all kinds of situations. For example, say you want to put your all-time favorite family picture in an 8x10 frame but the aspect ratio (Choosing a Background) isn’t quite right, the background isn’t big enough, or the photo’s subjects need to be a little bit closer together. In any of these circumstances, CAS can help. You can use it on layers and selections in RGB, CMYK, Lab, and Grayscale image modes (Choosing a Color Mode) and at all bit depths (see the box on Understanding Bit Depth). However, you can’t ...