Photoshop Express edits are non-destructive, which means anything you do in the editor won't permanently change the original image you uploaded. The software keeps track of which changes you make to the image and displays the results of those changes. So, for example, if you convert to black and white, Express notes that color is not being displayed, rather than removing the color information altogether. You can always roll back to a previous edit.
Step through edits
Each time you make an adjustment, Photoshop Express treats it as a separate step. To undo the last edit you applied, click the Undo button beneath the image (Figure 4.10). Similarly, if you've hit Undo too many times, click the Redo button to apply more recent edits.
Figure 4.10 Undo button.
A more visual approach is to view the edits you've made as tiles. Click the triangle icon between the Undo and Redo buttons to display the edit tiles (Figure 4.11).
Figure 4.11 Edit tiles.
Instead of repeatedly clicking the Undo or Redo buttons, click a tile to go back to any previous state. Hovering over a tile notes its type of edit.
Adjustments are linear: If you click an earlier tile, any edits that follow it will be discarded if you make a new adjustment.