Cropping an image is used to make a smaller image (in pixels) or to change the aspect ratio of the image. Cropping a photo can help you remove unwanted or irrelevant detail from a photo or get the composition you want.
To "crop" a photo you need to do the following:
From edit screen tap "Edit Cutout"
Tap the "crop" icon next to "?"
Tap and drag the marked edges to remove a part of the image
Tap "Done" to save changes