Cut away the parts of a picture that are not needed. Set the crop box in pixels, check the outlined preview, and download the result.
The crop box is measured in the image's own pixels from its top-left corner. The preview draws the full picture with the kept region outlined, at a reduced size — the download itself is produced at full resolution from the original file, so no quality is lost beyond the cropping. Output keeps the input format (JPG stays JPG, PNG stays PNG).
Why do the numbers change when a shape is picked? Quick shapes tie height to width using the chosen ratio, so the box cannot drift into the wrong proportions — useful for profile pictures and social posts with fixed shapes.
Is the cropped area the full quality original? Yes. Cropping reads pixels from the original file; it does not re-photograph the preview. The only reduction is the area outside the box, which is discarded.