Let's say you have an image you would like to crop. In this example, the yellow flower will be cropped.
- Open the image in Gimp and press Shift C (or Tools -> Transform Tools -> Crop)
- Drag a rectangular shape around the area you want to crop. In this example, a rectangle is placed around the yellow flow.
- Double left click in the cropped area to eliminate the uncropped area. Now only the cropped area will be displayed.
- Press Ctrl + Shift + E (or select File > Export As).
- Select Export twice.