One of the most basic image editing operations is rotation and cropping.
Often it is difficult to hold your camera steady especially when you are snapping pictures “on the go”. In this example I deliberately tilted the image before saving it. Typically you want the eyes of the mannequin to be level, so I dragged two guide lines from the graduated inch scales on the edges of the workspace to convenient reference points. In this case the nose and the left edge where the upper and lower eye lids meet. These lines stay stationary when you tilt the image. Next you select the “rotation” tool from the docker panel on the left. Or you can find it in the “Tools” – “Transform Tools” – “Rotate” from the top menu bar. And if you can remember it the keyboard shortcut is “CTRL – R”. This will bring up the rotation dialogue box and a number of grid lines. I find these quite confusing, as they will rotate with the image and cause confusion with the stationary guide lines. So I set the number of gridlines to to one. Next drag the crosshairs of the rotation center to the point around which you want to rotate. I this case the left edge of the left eye, where the eye lids meet. Now it is a simple matter of increasing or decreasing the angle in the dialogue box until the right edge of the right eye lines up with the guide line. Then click the Rotate button in the dialogue box and wait for GIMP to complete the rotation.
Next comes cropping. Select the “Crop” tool from the tool menu. Or you can find it in the “Tools” – “Transform Tools” – “Crop” from the top menu bar. And if you can remember it the keyboard shortcut is “CTRL – C”. The cursor symbol changes to a knife and you can drag a “cutting mask” over the picture by holding down the mouse button and dragging a rectangle. You will notice square handle areas in the corners. You can move the cursor in these boxes and adjust the cutting mask. If you move the mouse elsewhere the cursor changes into crossed arrows and you can then move the complete mask as is around the picture. When you are satisfied hit the Enter key and the area outside of the mask is deleted. What you see now is a checkerboard pattern outside of the image that remains. This is called the “Canvas”. You need to perform one more action to delete the excess canvas. You do this by selecting from the top menu “Image” – “Fit Canvas to Layer”. Now you are ready to save your cropped image.
Note: The “File” – “Save” or “File” – “Save As” operation will save the final result in the native GIMP xcf format, which can only be read by GIMP. If you want to use your image elsewhere, you have to EXPORT it. Goto “File” – “Export As” and select the format you want, such as JPG. I recommend you change the name to something like “Imagename-cropped.jpg” then hit the Export button. You will then get a dialogue box that will ask you what quality you would like to export your image to. If you want to further enhance your picture choose the maximum.