It’s because of the min values of $previewWidth, $previewHeight, $minWidth and $minHeight in the ManualImageCropEditorWindow.php.
It just happens with small source images, as far as i can say. Beaause of the min values the crop stage doesnt work correct if the image is smaller. Could fix this for me with editing the plugin file but should be a better solution. Spend defenitely too much in researching this bug.
Beside this excellent plugin.
Cheers.
