How to crop photos in iPhoto?

1.Select the photo you want to crop.

2.Click the Edit button.

3.Position the arrow pointer at one corner of the area you want to select, then drag to enclose the desired area. To constrain your selection to a specific size ratio, choose a ratio from the Constrain pop-up menu before dragging to enclose the desired area. If you're ordering larger prints, choose the appropriate size (5 x 7 or 8 x 10) to constrain the image.

4.Click the Crop icon in the Edit pane.

Here I share you iCollage for Mac that can perfectly help you edit your photos on Mac.