You can remove blemishes and other small marks from a photo.
Important: Editing a photo changes its appearance in the photo library and in every album, slideshow, and project (such as a book, card, or calendar) that it’s used in. To edit a photo without changing it everywhere it appears, duplicate the photo and edit the duplicate.
To retouch a photo:
Open the photo in edit view.
If the Quick Fixes tab (at the top of the Edit pane) isn’t selected, click it.
Click the Retouch button.
Drag the Size slider to select a brush size.
You can also change the brush size by pressing the Left Bracket ( [ ) and Right Bracket ( ] ) keys.
Position the brush over the mark you want to remove, and then click the mark or drag across it to remove it.
If the mark is small, try clicking a few times over the spot. If that doesn’t remove the mark, or the mark is larger, drag in short strokes to blend it into its surrounding colors.
Tip: If you’re not getting the results you want, you can “grab” pixels from another part of the photo and apply them to the blemish. Press the Option key while you click an area that has the texture you want, then do step 5.
Do one of the following:
To save your changes, click Done.
To cancel only the change you made using the Retouch tool, click Undo.
To cancel all changes made during this edit session (in any of the Edit panes), click “Revert to Previous.”