Decide where the image will appear before cropping: a square avatar, wide card, or document illustration each needs different framing. Keep the subject fully visible and leave room for interface overlays or circular masks.
Use the image cropper on the highest-quality source you have. Avoid repeatedly cropping and resaving a small copy. Preview the export at its real display size, especially on a phone. Check important edges, text, and faces after the final aspect ratio is applied; a good full-size crop can still fail as a thumbnail.
Save the original so you can reframe later without losing pixels.
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