Content-Aware Scale resizes an image without changing important visual content such as people, buildings, animals, and so forth. While normal scaling affects all pixels uniformly when resizing an image, content-aware scaling mostly affects pixels in areas that don’t have important visual content. Content-Aware Scale lets you upscale or downscale images to improve a composition, fit a layout, or change the orientation. If you want to use some normal scaling when resizing your image, there is an option for specifying a ratio of content-aware scaling to normal scaling.
If you want to preserve specific areas when scaling an image, Content-Aware Scale lets you use an alpha channel to protect content during resizing.
Content-aware scaling works on layers and selections. Images can be in RGB, CMYK, Lab, and Grayscale color modes as well as all bit depths. Content-aware scaling doesn’t work on adjustment layers, layer masks, individual channels, Smart Objects, 3D layers, Video layers, multiple layers simultaneously, or layer groups.