Today’s Question: You said that a non-destructive crop in Photoshop causes the cropped pixels to just be hidden from view. But how do you get those pixels back if you change your mind about the crop?
Tim’s Quick Answer: To reveal pixels that extend beyond the current image canvas area in Photoshop you can simply choose Image > Reveal All from the menu.
More Detail: As noted in yesterday’s answer, in Photoshop it is possible to crop non-destructively, which essentially means hiding cropped pixels from view rather than deleting them altogether.
There are other reasons that pixels may extend beyond the image canvas area as well. For example, when working on a composite image you might drag one of the layers into a position that extends beyond the canvas area.
If you later want to reveal the pixels that extend beyond the edge of the canvas, you can simply extend the canvas. One option for this is the Reveal All command found on the Image menu. This will cause the canvas to be expanded to the outer bounds of all pixels that are currently outside the canvas area.
You can also exercise control over the specific extent to which the canvas is extended, rather than simply expanding it to reveal all pixels. You could use the Crop tool, for example, and drag the crop box outward to the extent desired on any or all sides of the image.
You could also use the Canvas Size command, also found on the Image menu, to expand the canvas in one or more directions to a specific extent. Within the Canvas Size dialog you can specify the amount you want to extend the canvas horizontally and vertically, and designate an anchor position to determine in which directions the canvas will be expanded.