I find it puzzling that every time I've cropped an image with Photo Viewer, I'm unable to change the aspect ratio of the crop region (it remains the same as the aspect ratio of the original image). I'm not sure whether Photo Viewer on elementary is the same as the Shotwell Photo Viewer on Ubuntu, which has a small configuration popup when cropping, but the app looks very similar, so I'm thinking the configuration popup should be accessible somewhere? Or if the app isn't the same, is it meant to be this way?
The aspect ratio can be changed:
To enable it, try running this command:
gsettings reset-recursively org.yorba.shotwell.crop-settings
On elementary OS Loki 0.4, I solved the problem by installing dconf-editor
sudo apt-get install dconf-editor
Then with dconf-editor navigate to org/panthenon/photos/crop-settings and set
last-crop-height values to
Please note it should be exactly zero otherwise it will not work!